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As filed with the Securities and Exchange Commission on October 26, 2017

Registration No. 333-          


UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM S-4
REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933



LITTELFUSE, INC.
(Exact name of registrant as specified in its charter)



Delaware
(State or other jurisdiction of
incorporation or organization)
  3613
(Primary Standard Industrial
Classification Code Number)
  36-3795742
(I.R.S. Employer
Identification Number)



8755 West Higgins Road, Suite 500
Chicago, Illinois 60631
(773) 628-1000
Address, including zip code, and telephone number, including area code, of registrant's principal executive offices)

Ryan K. Stafford, Esq.
Executive Vice President, Chief Legal and
Human Resources Officer and Corporate Secretary
Littelfuse, Inc.
8755 West Higgins Road, Suite 500
Chicago, Illinois 60631
(773) 628-1000
(Name, address, including zip code, and telephone number, including area code, of agent for service)



With copies to:

Edward D. Herlihy, Esq.
Mark F. Veblen, Esq.
Wachtell, Lipton, Rosen & Katz
51 West 52nd Street
New York, New York 10019
(212) 403-1000

 

James R. Jones, Esq.
Vice President and General Counsel
IXYS Corporation
1590 Buckeye Drive
Milpitas, California 95035-7418
(408) 457-9000

 

Luke J. Bergstrom, Esq.
Chad G. Rolston, Esq.
Latham & Watkins LLP
140 Scott Drive
Menlo Park, California 94025
(650) 328-4600

Approximate date of commencement of proposed sale of the securities to the public:
As soon as practicable after this Registration Statement is declared effective and upon the satisfaction or waiver of all
other conditions to consummation of the transactions described herein.

             If the securities being registered on this Form are being offered in connection with the formation of a holding company and there is compliance with General Instruction G, check the following box.    o

             If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.    o

             If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.    o

             Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

Large accelerated filer ý   Accelerated filer o   Non-accelerated filer o
(Do not check if a
smaller reporting company)
  Smaller reporting company o

Emerging growth company o

             If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. o

             If applicable, place an X in the box to designate the appropriate rule provision relied upon in conducting this transaction:

                 Exchange Act Rule 13e-4(i) (Cross-Border Issuer Tender Offer)    o

                 Exchange Act Rule 14d-1(d) (Cross-Border Third-Party Tender Offer)    o



CALCULATION OF REGISTRATION FEE

               
 
Title of Each Class of Securities
to Be Registered

  Amount to Be
Registered(1)

  Proposed Maximum
Offering Price
Per Share

  Proposed Maximum
Aggregate Offering
Price(2)

  Amount of
Registration Fee(3)

 

Common Stock, par value $0.01 per share

  2,827,860   N/A   $422,760,306   $52,633.66

 

(1)
Represents the maximum number of shares of common stock, par value $0.01 per share, of Littelfuse, Inc. estimated to be issuable, or subject to options that are to be assumed by Littelfuse, at the effective time of the initial merger, as described herein, of a subsidiary of Littelfuse with and into IXYS Corporation. The number of shares of Littelfuse common stock being registered is equal to the product obtained by multiplying (i) 22,354,626 shares of IXYS common stock, par value $0.01 per share, by (ii) the exchange ratio of 0.1265 of a share of Littelfuse common stock for each share of IXYS common stock entitled to receive Littelfuse common stock in the merger. The number of shares of IXYS common stock set forth in clause (i) of the prior sentence is equal to (A) 50% of the estimated maximum number of shares of IXYS common stock that may be canceled and exchanged in the merger, plus (B) 5,936,750 shares of IXYS common stock subject to IXYS options outstanding as of October 16, 2017 or that may be granted after such date and prior to the effective time of the merger. The estimated maximum number of shares of IXYS common stock that may be canceled and exchanged in the merger is equal to the sum of (x) 32,765,103 shares of IXYS common stock outstanding as of October 16, 2017, plus (y) 70,648 shares of IXYS common stock that may be issued under the IXYS employee stock purchase plan prior to the effective time of the merger. Consideration in the merger is subject to proration, as described herein, so that 50% of the shares of IXYS common stock outstanding immediately prior to the effective time of the merger will be converted into cash and the remaining shares of IXYS common stock will be converted into Littelfuse common stock at the exchange ratio described above.

(2)
Estimated solely for the purpose of calculating the registration fee required by Section 6(b) of the Securities Act and calculated in accordance with Rules 457(c), 457(f)(1) and 457(f)(3) under the Securities Act, based on (i) the market value of the estimated maximum number of shares of IXYS common stock that may be canceled and exchanged in the merger (as set forth in the preceding footnote), as established by the average of the high and low sales prices of IXYS common stock on The NASDAQ Global Select Market on October 16, 2017 of $24.38, minus (ii) $377,611,125, which is the aggregate amount of cash estimated to be paid by Littelfuse to IXYS' stockholders in the merger. The aggregate amount of cash set forth in clause (ii) of the prior sentence is equal to the product obtained by multiplying (A) $23.00 by (B) the number that is equal to 50% of the estimated maximum number of shares of IXYS common stock that may be canceled and exchanged in the merger (as set forth in the preceding footnote).

(3)
Calculated by multiplying the estimated aggregate offering price of securities to be registered by Littelfuse by 0.0001245.



             The registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until this Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

   


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The information in this proxy statement/prospectus is subject to completion and amendment. A registration statement relating to the securities described in this proxy statement/prospectus has been filed with the Securities and Exchange Commission. These securities may not be sold nor may offers to buy these securities be accepted prior to the time the registration statement becomes effective. This proxy statement/prospectus shall not constitute an offer to sell or the solicitation of any offer to buy nor shall there be any sale of these securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration under the securities laws of any such jurisdiction.

PRELIMINARY—SUBJECT TO COMPLETION, DATED OCTOBER 26, 2017

LOGO

MERGER PROPOSED—YOUR VOTE IS VERY IMPORTANT

Dear IXYS Corporation Stockholder:

          On August 25, 2017, IXYS Corporation (referred to as IXYS), Littelfuse, Inc. (referred to as Littelfuse) and Iron Merger Co., Inc., a wholly owned subsidiary of Littelfuse (referred to as Merger Sub), entered into an Agreement and Plan of Merger that provides for the acquisition of IXYS by Littelfuse (such agreement, as it may be amended from time to time, is referred as the merger agreement). Pursuant to the terms of the merger agreement, Merger Sub will merge with and into IXYS (referred to as the initial merger), with IXYS continuing as the surviving corporation in the initial merger and a wholly owned subsidiary of Littelfuse. Further to the terms of the merger agreement, IXYS, as the surviving corporation of the initial merger, will merge with and into Littelfuse (or a subsidiary of Littelfuse) (referred to as the follow-on merger, and collectively with the initial merger, the merger), with Littelfuse (or such subsidiary) continuing as the surviving corporation in the follow-on merger. The respective boards of directors of IXYS and Littelfuse have unanimously approved the merger agreement, the merger and the other transactions contemplated by the merger agreement.

          Upon the terms and subject to the conditions of the merger agreement, at the effective time of the initial merger (referred as the effective time), each share of common stock, par value $0.01 per share, of IXYS that you own immediately prior to the effective time will be cancelled and extinguished and automatically converted into the right to receive, at your election and subject to proration, (i) $23.00 in cash (subject to applicable withholding tax), without interest (referred to as the cash consideration), or (ii) 0.1265 of a share of common stock, par value $0.01 per share, of Littelfuse (referred to as the stock consideration and together with the cash consideration, the merger consideration). You will receive cash in lieu of any fractional shares of Littelfuse common stock that you would otherwise be entitled to receive. Additionally, at the effective time, each outstanding option to purchase shares of IXYS common stock granted under an IXYS equity plan will be assumed by Littelfuse and converted into an option to acquire (i) a number of shares of Littelfuse common stock equal to the number of shares of IXYS common stock subject to such option immediately prior to the effective time multiplied by 0.1265, rounded down to the nearest whole share, with (ii) an exercise price per share of Littelfuse common stock equal to the exercise price of such IXYS stock option immediately prior to the effective time divided by 0.1265, rounded up to the nearest whole cent.

          Based on the closing stock price of Littelfuse common stock on August 25, 2017, the last full trading day before the announcement of the merger, the per share value of IXYS common stock implied by the stock consideration is $22.55. Based on the closing stock price of Littelfuse common stock on [    ·    ], 2017, the most recent practicable date prior to the date of the accompanying proxy statement/prospectus, the per share value implied by the stock consideration is $[    ·    ], which represents a premium of approximately [    ·    ]% over IXYS' closing stock price on August 25, 2017. The implied value of the stock consideration will fluctuate as the market price of Littelfuse common stock fluctuates because the stock consideration is payable in a fixed number of shares of Littelfuse common stock. As a result, the value of the stock consideration that IXYS stockholders will receive upon completion of the merger could be greater than, less than or the same as the value of the stock consideration on the date of the accompanying proxy statement/prospectus or at the time of the special meeting of the IXYS stockholders described in the accompanying proxy statement/prospectus (referred to as the special meeting). Accordingly, you should obtain current stock price quotations for Littelfuse common stock and IXYS common stock before deciding how to vote with respect to the approval of the merger proposal. Littelfuse common stock and IXYS common stock trade on The NASDAQ Global Select Market under the symbols "LFUS" and "IXYS," respectively.

          Based on the number of shares of Littelfuse common stock and IXYS common stock outstanding on October 16, 2017, upon completion of the merger, former IXYS stockholders will own approximately 8% of the outstanding shares of Littelfuse common stock and Littelfuse stockholders immediately prior to the merger will own approximately 92% of the outstanding shares of Littelfuse common stock.

          The IXYS board of directors unanimously determined that the merger and the merger agreement are fair to and in the best interests of IXYS and its stockholders, and approved and declared it advisable to enter into the merger agreement.

          At the special meeting, you will be asked to approve the merger proposal and to vote on other merger-related matters. The IXYS board of directors unanimously recommends that IXYS stockholders vote "FOR" the merger proposal and "FOR" each of the other proposals described in the accompanying proxy statement/prospectus.

          Your vote is very important.    Littelfuse and IXYS cannot complete the merger without the approval of the merger proposal by IXYS stockholders holding at least a majority of the shares of IXYS common stock outstanding at the close of business on [    ·    ], 2017, the record date for the special meeting. The failure of any stockholder to vote will have the same effect as a vote against the approval of the merger proposal. It is important that your shares of IXYS common stock be represented and voted regardless of the size of your holdings. Whether or not you plan to attend the special meeting, IXYS urges you to submit a proxy in advance of the special meeting to have your shares voted by using one of the methods described in the accompanying proxy statement/prospectus.

          More information about Littelfuse, IXYS, the special meeting, the merger and the other proposals for consideration at the special meeting is contained in the accompanying proxy statement/prospectus. Please carefully read the entire proxy statement/prospectus, including the section titled "Risk Factors" beginning on page 31, for a discussion of the risks relating to the proposed merger, and the annexes and documents incorporated by reference.

On behalf of the IXYS board of directors, thank you for your continued support.

Sincerely,

Uzi Sasson
President and Chief Executive Officer

          NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED THE MERGER OR OTHER TRANSACTIONS DESCRIBED IN THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS OR THE SECURITIES TO BE ISSUED PURSUANT TO THE MERGER UNDER THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS NOR HAVE THEY DETERMINED IF THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS IS ACCURATE OR ADEQUATE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

          The accompanying proxy statement/prospectus is dated [    ·    ], 2017 and is first being mailed to IXYS stockholders on or about [    ·    ], 2017.


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LOGO

IXYS CORPORATION
1590 Buckeye Drive
Milpitas, California 95035-7418

NOTICE OF SPECIAL MEETING OF STOCKHOLDERS TO BE HELD ON [    ·    ], 2017

        This is a notice that the special meeting of stockholders of IXYS Corporation (referred to as IXYS) will be held on [    ·    ], 2017, beginning at [    ·    ], local time, at IXYS' principal executive offices at the above address, unless postponed to a later date. The special meeting will be held for the following purposes:

    1.
    to adopt the Agreement and Plan of Merger, dated as of August 25, 2017 (such agreement, as it may be amended from time to time, is referred to as the merger agreement), by and among IXYS, Littelfuse, Inc. (referred to as Littelfuse) and Iron Merger Co., Inc., a wholly owned subsidiary of Littelfuse (referred to as Merger Sub), pursuant to which, upon the terms and subject to the conditions of the merger agreement, Merger Sub will merge with and into IXYS (referred to as the initial merger), with IXYS surviving the initial merger as a wholly owned subsidiary of Littelfuse, and further to which IXYS, as the surviving corporation of the initial merger, will merge with and into Littelfuse (or a subsidiary of Littelfuse) (referred to as the follow-on merger, and collectively with the initial merger, the merger), with Littelfuse (or such subsidiary) continuing as the surviving corporation in the follow-on merger (referred to as the merger proposal);

    2.
    to approve on an advisory (non-binding) basis the compensation that may be paid or become payable to IXYS' named executive officers that is based on or otherwise relates to the merger (referred to as the merger-related compensation proposal); and

    3.
    to approve the adjournment of the special meeting, if necessary, to solicit additional proxies if there are not sufficient votes to approve the merger proposal (referred to as the adjournment proposal).

        The accompanying proxy statement/prospectus describes the proposals listed above in more detail. Please refer to the accompanying proxy statement/prospectus, including the merger agreement and the other annexes and documents included in, or incorporated by reference into, the accompanying proxy statement/prospectus for further information with respect to the business to be transacted at the special meeting. You are encouraged to read the entire proxy statement/prospectus carefully before voting. In particular, see the section titled "Risk Factors" beginning on page 31.

        The IXYS board of directors unanimously determined that the terms of the merger agreement and the merger are fair to, and in the best interests of, IXYS and its stockholders, and that it is in the best interests of IXYS and its stockholders, and declared it advisable, for IXYS to enter into the merger agreement. The IXYS board of directors recommends that IXYS stockholders vote "FOR" the merger proposal and "FOR" each of the other proposals listed above and described in more detail in the accompanying proxy statement/prospectus.

        The IXYS board of directors has fixed the close of business on [    ·    ], 2017 as the record date for determination of IXYS stockholders entitled to receive notice of, and to vote at, the special meeting or any adjournments or postponements thereof. Only holders of record of IXYS common stock as of the close of business on the record date are entitled to receive notice of, and to vote at, the special meeting.

        YOUR VOTE IS VERY IMPORTANT, REGARDLESS OF THE NUMBER OF SHARES THAT YOU OWN.


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        The merger cannot be completed unless the merger proposal is approved by the affirmative vote, in person or by proxy, of holders of a majority of the outstanding shares of IXYS common stock entitled to vote thereon.

        The affirmative vote of holders of a majority of the shares of IXYS common stock present in person or represented by proxy at the special meeting and entitled to vote thereon is required to approve the merger-related compensation proposal and the adjournment proposal.

        Whether or not you expect to attend the special meeting in person, IXYS urges you to submit a proxy to have your shares voted as promptly as possible by either: (1) logging onto the website shown on your proxy card and following the instructions to submit a proxy online; (2) dialing the toll-free number shown on your proxy card and following the instructions to submit a proxy by phone; or (3) signing and returning the enclosed proxy card in the postage-paid envelope provided, so that your shares may be represented and voted at the special meeting. If your shares are held in the name of a bank, brokerage firm or other nominee, please follow the instructions on the voting instruction card furnished by such bank, brokerage firm or other nominee. Any stockholder of record attending the special meeting may vote in person even if such stockholder has returned a proxy card.

        If you have any questions about the special meeting, the merger, the proposals or the accompanying proxy statement/prospectus, would like additional copies of the proxy statement/prospectus, need to obtain proxy cards or other information related to this proxy solicitation or need help submitting a proxy or voting your shares of IXYS common stock, you should contact:

IXYS Corporation
1590 Buckeye Drive
Milpitas, CA 95035
(408) 457-9000
Attention: Investor Relations

or

D.F. King & Co., Inc.
48 Wall Street
New York, NY 10005

Banks and Brokerage Firms Call: (212) 493-3910
Stockholders Call Toll Free: (800) 334-0384
Email: ixys@dfking.com

By order of the board of directors

Uzi Sasson
President and Chief Executive Officer

Dated: [    ·    ], 2017
Milpitas, California


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ADDITIONAL INFORMATION

        This proxy statement/prospectus incorporates important business and financial information about Littelfuse and IXYS from other documents that Littelfuse and IXYS have filed with the U.S. Securities and Exchange Commission (referred to in this proxy statement/prospectus as the SEC) and that are contained in or incorporated by reference into this proxy statement/prospectus. For a listing of documents incorporated by reference into this proxy statement/prospectus, please see the section titled "Where You Can Find More Information" beginning on page 150. This information is available for you to review at the SEC's public reference room located at 100 F Street, N.E., Room 1580, Washington, DC 20549, and through the SEC's website at www.sec.gov.

        You can obtain copies of this proxy statement/prospectus and the documents incorporated by reference into this proxy statement/prospectus free of charge by requesting them in writing or by telephone at the following addresses and telephone numbers:

For Information Regarding Littelfuse:   For Information Regarding IXYS:

Littelfuse, Inc.

 

IXYS Corporation
8755 West Higgins Road, Suite 500   1590 Buckeye Drive
Chicago, Illinois 60631   Milpitas, California 95035
(773) 628-1000   (408) 457-9000
Attention: Investor Relations   Attention: Investor Relations

        In addition, if you have questions about the special meeting, the merger, the proposals or this proxy statement/prospectus, would like additional copies of the proxy statement/prospectus, need to obtain proxy cards or other information related to the proxy solicitation or need help submitting a proxy or voting your shares of IXYS common stock, you may contact D.F. King & Co., Inc. (referred to in this proxy statement/prospectus as D.F. King or IXYS' proxy solicitor), at the address and telephone number listed below. You will not be charged for any of these documents that you request.

D.F. King & Co., Inc.
48 Wall Street
New York, NY 10005

Banks and Brokerage Firms Call: (212) 493-3910
Stockholders Call Toll Free: (800) 334-0384
Email: ixys@dfking.com

        If you would like to request any documents, please do so by [    ·    ], 2017, which is the date that is five business days prior to the date of the special meeting, in order to receive them before the special meeting.


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ABOUT THIS PROXY STATEMENT/PROSPECTUS

        This proxy statement/prospectus, which forms part of a registration statement on Form S-4 (Registration No. 333-[    ·    ]) filed with the SEC by Littelfuse, constitutes a prospectus of Littelfuse under the Securities Act of 1933, as amended (referred to in this proxy statement/prospectus as the Securities Act), with respect to the Littelfuse common stock to be issued to IXYS stockholders pursuant to the merger. This proxy statement/prospectus also constitutes a proxy statement for IXYS under the Securities Exchange Act of 1934, as amended (referred to in this proxy statement/prospectus as the Exchange Act), and a notice of meeting with respect to the special meeting of IXYS stockholders.

        You should rely only on the information contained in or incorporated by reference into this proxy statement/prospectus. No one has been authorized to provide you with information that is different from that contained in, or incorporated by reference into, this proxy statement/prospectus. This proxy statement/prospectus is dated [    ·    ], 2017, and you should assume that the information contained in this proxy statement/prospectus is accurate only as of such date. You should also assume that the information incorporated by reference into this proxy statement/prospectus is accurate only as of the date of such information.

        This proxy statement/prospectus does not constitute an offer to sell, or a solicitation of an offer to buy, any securities, or the solicitation of a proxy in any jurisdiction to or from any person to whom it is unlawful to make any such offer or solicitation in such jurisdiction. Information contained in this proxy statement/prospectus regarding Littelfuse has been provided by Littelfuse, and information contained in this proxy statement/prospectus regarding IXYS has been provided by IXYS.


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TABLE OF CONTENTS

QUESTIONS AND ANSWERS

    1  

SUMMARY

    11  

The Parties

    11  

The Merger and the Merger Agreement

    11  

Merger Consideration

    12  

IXYS Special Meeting

    13  

How Proxies Are Counted; Failure to Vote; Abstentions and Broker Non-Votes

    14  

IXYS' Reasons for the Merger; Recommendation of the IXYS Board of Directors

    14  

Opinion of IXYS' Financial Advisor

    14  

Interests of IXYS' Directors and Executive Officers in the Merger

    15  

Material U.S. Federal Income Tax Consequences

    15  

Accounting Treatment of the Merger

    16  

Regulatory Approvals Required to Complete the Merger

    16  

Expected Timing of Merger

    16  

Treatment of IXYS Stock Options

    16  

Listing of Littelfuse Common Stock; Delisting of IXYS Common Stock

    17  

Appraisal Rights

    17  

No Solicitation of Company Takeover Proposals

    17  

Changes in Board Recommendation

    18  

Conditions to Completion of the Merger

    18  

Termination of the Merger Agreement

    19  

Expenses and Termination Fees Relating to the Merger

    20  

Comparison of Rights of Common Stockholders of Littelfuse and IXYS

    20  

Risk Factors

    20  

SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA

    21  

Selected Historical Consolidated Financial Data of Littelfuse

    21  

Selected Historical Consolidated Financial Data of IXYS

    23  

UNAUDITED COMPARATIVE PER SHARE INFORMATION

    26  

COMPARATIVE STOCK PRICE DATA AND DIVIDENDS

    27  

Stock Prices

    27  

Littelfuse Common Stock

    27  

IXYS Common Stock

    28  

Dividends

    28  

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

    29  

RISK FACTORS

    31  

Risks Relating to the Merger

    31  

Other Risk Factors of Littelfuse and IXYS

    38  

INFORMATION ABOUT IXYS

    39  

INFORMATION ABOUT LITTELFUSE

    39  

INFORMATION ABOUT THE IXYS SPECIAL MEETING

    40  

General

    40  

Date, Time and Place of the Special Meeting

    40  

Purposes of the Special Meeting

    40  

Only the approval of the merger proposal is required for completion of the merger. 

    40  

Attendance at the Special Meeting

    40  

Record Date

    41  

Outstanding Shares As of Record Date

    41  

Shares and Voting of IXYS' Directors and Executive Officers

    41  

Quorum and Broker Non-Votes

    42  

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Required Vote

    42  

How To Vote or Have Your Shares Voted

    43  

Revocation of Proxies

    44  

Solicitation of Proxies

    44  

Adjournments

    44  

Questions and Additional Information

    45  

PROPOSAL 1: THE MERGER PROPOSAL

    46  

PROPOSAL 2: THE MERGER-RELATED COMPENSATION PROPOSAL

    47  

PROPOSAL 3: THE ADJOURNMENT PROPOSAL

    48  

THE MERGER

    49  

Merger Consideration

    49  

Background of the Merger

    50  

IXYS' Reasons for the Merger; Recommendation of IXYS Board of Directors

    55  

Certain Financial Projections Utilized by the IXYS Board of Directors and IXYS' Financial Advisor

    60  

Opinion of IXYS' Financial Advisor

    64  

Form of Merger

    73  

Interests of IXYS' Directors and Executive Officers in the Merger

    74  

Quantification of Potential Payments and Benefits to IXYS' Named Executive Officers in Connection with the Merger

    77  

Narrative Disclosure to Golden Parachute Compensation Table

    79  

Accounting Treatment of the Merger

    79  

Material U.S. Federal Income Tax Consequences

    79  

Regulatory Approvals

    83  

Exchange of Shares; Elections As to Form of Consideration

    84  

Dividend Policy

    86  

Listing of Littelfuse Common Stock; Delisting of IXYS Common Stock

    87  

THE MERGER AGREEMENT

    88  

Closing; Effective Time

    88  

Effect of the Merger on Capital Stock

    89  

Election Procedures

    92  

Exchange and Payment Procedures

    93  

Treatment of IXYS Equity Awards

    95  

Representations and Warranties

    96  

Conduct of Businesses of IXYS and Littelfuse Prior to Completion of the Merger

    98  

No Solicitation of Company Takeover Proposals

    101  

No Change in Recommendation or Termination For a Superior Proposal

    103  

IXYS Stockholder Meeting

    105  

Actions with Respect to IXYS Debt

    105  

Access to Information

    105  

Employee Matters

    106  

Indemnification and Insurance

    106  

Littelfuse Board of Directors

    107  

Certain Additional Covenants

    107  

Conditions to Completion of the Merger

    108  

Regulatory Approvals

    109  

Termination of the Merger Agreement

    109  

Amendment and Assignment

    111  

Jurisdiction; Specific Enforcement

    111  

THE VOTING AGREEMENT

    113  

OTHER MATTERS

    113  

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UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

    114  

NOTES TO THE UNAUDTED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS GIVING EFFECT TO THE TRANSACTION

    118  

DESCRIPTION OF LITTELFUSE CAPITAL STOCK

    125  

Common Stock

    125  

Potential Anti-Takeover Effects of Various Provisions of Delaware Law and Littelfuse's Certificate of Incorporation and Bylaws

    125  

COMPARISON OF RIGHTS OF COMMON STOCKHOLDERS OF LITTELFUSE AND IXYS

    127  

APPRAISAL RIGHTS OF IXYS STOCKHOLDERS

    142  

LEGAL MATTERS

    147  

EXPERTS

    147  

Littelfuse

    147  

IXYS

    147  

IXYS 2018 STOCKHOLDER PROPOSALS

    148  

HOUSEHOLDING OF PROXY STATEMENT/PROSPECTUS

    149  

WHERE YOU CAN FIND MORE INFORMATION

    150  

Annex A—Agreement and Plan of Merger, dated as of August 25, 2017, by and among IXYS Corporation, Littelfuse, Inc. and Iron Merger Co., Inc.

   
 

Annex B—Voting Agreement, dated as of August 25, 2017, by and between Littelfuse,  Inc. and Dr. Nathan Zommer, Sharkz, L.P., The Nathan Zommer Dynasty Trust Dated July 17, 2006 and the Nathan Zommer TTEE FBO Nathan Zommer Trust U/A/D 04-08-2003

       

Annex C—Opinion of Needham & Company, LLC

       

Annex D—General Corporation Law of the State of Delaware, Section 262

       

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QUESTIONS AND ANSWERS

        The following questions and answers are intended to briefly address some commonly asked questions regarding the merger, the merger agreement and the special meeting. These questions and answers may not address all questions that may be important to you as an IXYS stockholder. Please refer to the section titled "Summary" beginning on page 11 and the more detailed information contained elsewhere in this proxy statement/prospectus, the annexes to this proxy statement/prospectus and the documents referred to in this proxy statement/prospectus, which you should read carefully and in their entirety. You may obtain the information incorporated by reference into this proxy statement/prospectus without charge by following the instructions under the section titled "Where You Can Find More Information" beginning on page 150.

Q:    Why am I receiving this proxy statement/prospectus?

A:
IXYS Corporation (referred to in this proxy statement/prospectus as IXYS) is sending these materials to IXYS stockholders to help them decide how to vote their shares of IXYS common stock with respect to the adoption of the Agreement and Plan of Merger, dated as of August 25, 2017, by and among IXYS, Littelfuse, Inc. (referred to in this proxy statement/prospectus as Littelfuse) and Iron Merger Co., Inc., a wholly owned subsidiary of Littelfuse (referred to in this proxy statement/prospectus as Merger Sub), which agreement provides for the acquisition of IXYS by Littelfuse (such agreement, as it may be amended from time to time, is referred to in this proxy statement/prospectus as the merger agreement) and with respect to the other proposals to be considered at the special meeting of IXYS stockholders to be held on [    ·    ], 2017 (referred to in this proxy statement/prospectus as the special meeting).

    This document constitutes both a proxy statement of IXYS and a prospectus of Littelfuse. It is a proxy statement because IXYS is soliciting proxies from its stockholders. It is a prospectus because Littelfuse will issue shares of its common stock in exchange for shares of IXYS common stock in the merger if the merger is completed.

Q:    What is the merger?

A:
IXYS has agreed to be acquired by Littelfuse under the terms of the merger agreement, which is further described in this proxy statement/prospectus. If the merger agreement is adopted by IXYS stockholders and the other conditions to closing under the merger agreement are satisfied or waived, Merger Sub will merge with and into IXYS (referred to in this proxy statement/prospectus as the initial merger), with IXYS continuing as the surviving corporation in the initial merger and a wholly owned subsidiary of Littelfuse. Further to the terms of the merger agreement, IXYS, as the surviving corporation of the initial merger, will merge with and into Littelfuse (or a subsidiary of Littelfuse) (referred to in this proxy statement/prospectus as the follow-on merger, and collectively with the initial merger, the merger), with Littelfuse (or such subsidiary) continuing as the surviving corporation in the follow-on merger. Littelfuse intends to structure the follow-on merger as a merger of IXYS with and into a subsidiary of Littelfuse.

    The merger cannot be completed unless the merger proposal is approved by the affirmative vote, in person or by proxy, of holders of a majority of the outstanding shares of IXYS common stock entitled to vote thereon. Your failing to submit a proxy or vote in person at the special meeting, or your abstaining from voting or your failing to provide your bank, brokerage firm or other nominee with instructions on how to vote your shares, as applicable, will have the same effect as a vote "AGAINST" the merger proposal. The IXYS board of directors unanimously recommends that stockholders vote "FOR" the merger proposal. This proxy statement/prospectus includes important information about the merger and the merger agreement, a copy of which is attached as Annex A to this proxy statement/prospectus. IXYS stockholders should read this information carefully and in its entirety.

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Q:    Are there any risks that I should consider in deciding whether to vote for the approval of the merger proposal?

A:
Yes. You should read and carefully consider the risk factors set forth in the section titled "Risk Factors" beginning on page 31. You should also read and carefully consider the risk factors of Littelfuse and IXYS contained in the documents that are incorporated by reference into this proxy statement/prospectus.

Q:    What will IXYS stockholders receive for their shares if the merger is completed?

A:
At the effective time of the initial merger (referred to in this proxy statement/prospectus as the effective time), you will be entitled to receive, at your election and subject to proration, for each share of IXYS common stock that you hold, merger consideration equal to $23.00 in cash, without interest, less any applicable withholding taxes (referred to in this proxy statement/prospectus as the cash consideration), or 0.1265 of a share of Littelfuse common stock (referred to in this proxy statement/prospectus as the stock consideration and together with the cash consideration, the merger consideration). You will receive cash in lieu of any fractional shares of Littelfuse common stock that you would otherwise be entitled to receive.

    The merger consideration is subject to proration so that 50% of IXYS common stock issued and outstanding immediately prior to the effective time will be converted into cash consideration and the remaining IXYS common stock will be converted into stock consideration. You may elect to receive either the stock consideration or the cash consideration. However, the ability to receive the merger consideration of your choice will depend on the election of other IXYS stockholders. The proration of the merger consideration payable to IXYS stockholders in the merger will not be known until IXYS tallies the results of the elections made by IXYS stockholders, which will not occur until immediately prior to or following the closing of the initial merger. Holders of IXYS common stock who do not make an election will be treated as having elected to receive cash consideration or stock consideration in accordance with the proration methodology in the merger agreement.

    Based on the closing stock price of Littelfuse common stock on August 25, 2017, the last full trading day before the announcement of the merger, the per share value of IXYS common stock implied by the stock consideration is $22.55. Based on the closing stock price of Littelfuse common stock on [    ·    ], 2017, the most recent practicable date prior to the date of this proxy statement/prospectus, the per share value of IXYS common stock implied by the stock consideration is $[    ·    ]. The implied value of the stock consideration will fluctuate as the market price of Littelfuse common stock fluctuates because the stock consideration is payable in a fixed number of shares of Littelfuse common stock. As a result, the value of the stock consideration that IXYS stockholders will receive upon completion of the merger could be greater than, less than or the same as the value of the stock consideration on the date of this proxy statement/prospectus or at the time of the IXYS special meeting. Accordingly, you should obtain current stock price quotations for Littelfuse common stock and IXYS common stock before deciding how to vote with respect to approval of the merger proposal.

    For additional information regarding the consideration to be received in the merger, see the section titled "The Merger—Merger Consideration" beginning on page 49.

Q:    What happens if I am eligible to receive a fraction of a share of Littelfuse common stock as part of the stock consideration?

A:
If the aggregate number of shares of Littelfuse common stock that you are entitled to receive as part of the stock consideration otherwise would include a fraction of a share of Littelfuse common

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    stock, you will receive cash in lieu of that fractional share. See the section titled "The Merger—Exchange of Shares" beginning on page 84.

Q:    What will holders of IXYS stock options receive in the merger?

A:
At the effective time, each outstanding and unexercised option to purchase shares of IXYS common stock granted by IXYS under one of its equity plans (each, an IXYS stock option) will be assumed by Littelfuse and converted into an option (each, a Littelfuse stock option) to acquire (i) that number of whole shares of Littelfuse common stock (rounded down to the nearest whole share) equal to the product of (x) the number of shares of IXYS common stock subject to such IXYS stock option immediately prior to the effective time multiplied by (y) 0.1265, (ii) at an exercise price per share of Littelfuse common stock (rounded up to the nearest whole cent) equal to the quotient of (x) the exercise price per share of IXYS common stock of such IXYS stock option divided by (y) 0.1265. Each IXYS stock option assumed and converted into a Littelfuse stock option will continue to have, and will be subject to, the same vesting schedule (including any accelerated vesting terms) and all other terms and conditions as applied to such IXYS stock option immediately prior to the effective time.

    See the section titled "The Merger Agreement—Treatment of IXYS Equity Awards" beginning on page 95.

Q:    How will IXYS stockholders make their election to receive either the cash consideration or the stock consideration in the merger?

A:
An election form will be mailed to each holder of record of IXYS common stock as of the business day immediately preceding the mailing. The mailing will occur at least 20 business days prior to the anticipated election deadline, which is expected to be 5:00 p.m. local time (in the city in which the principal office of the exchange agent is located) on the date Littelfuse and IXYS expect to be two business days before the closing date. Littelfuse will also make an election form available to each IXYS stockholder who requests such form before the election deadline. Each IXYS stockholder should complete and return the election form, along with IXYS stock certificate(s) (or a properly completed notice of guaranteed delivery, as set forth in the election form), according to the instructions included with the form. The election form will be provided to IXYS stockholders under separate cover and is not being provided with this document.

    If you own shares of IXYS common stock in "street name" through a bank, broker or other nominee and you wish to make an election, you should seek instructions from the bank, broker or other nominee holding your shares concerning how to make an election. If you do not send in the election form with your stock certificate(s) by the election deadline, you will be treated as though you had not made an election.

Q:    What happens if an IXYS stockholder does not make a valid election to receive either the cash consideration or the stock consideration?

A:
If an IXYS stockholder does not return a properly completed election form by the election deadline specified in the election form, such stockholder's shares of IXYS common stock will be considered "non-election" shares and will be converted into the right to receive the stock consideration or the cash consideration according to the allocation procedures specified in the merger agreement. Generally, in the event one form of merger consideration (i.e., cash or shares of Littelfuse common stock) is undersubscribed, shares of IXYS common stock for which no election was validly made will be allocated to that form of merger consideration before shares of IXYS common stock electing the oversubscribed form of merger consideration will be allocated to the undersubscribed form of merger consideration pursuant to the proration and adjustment

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    procedures. Accordingly, although electing one form of merger consideration will not guarantee you will receive that form of merger consideration for all of your shares of IXYS common stock, in the event proration is necessary, electing shares will be allocated the undersubscribed form of consideration only after such consideration is allocated to "non-election" shares.

Q:    How will I receive the merger consideration to which I am entitled?

A:
After receiving the proper documentation from you, following completion of the initial merger, the exchange agent for the merger (referred to in this proxy statement/prospectus as the exchange agent) will forward to you the stock consideration and/or cash consideration to which you are entitled. More information on the documentation you are required to deliver to the exchange agent may be found in the section titled "The Merger Agreement—Exchange and Payment Procedures" beginning on page 93.

Q:    What will happen to IXYS as a result of the merger?

A:
If the merger is completed, IXYS, as the surviving corporation of the initial merger, will merge with and into Littelfuse (or a subsidiary of Littelfuse), with Littelfuse (or such subsidiary) continuing as the surviving corporation in the follow-on merger. Littelfuse intends to structure the follow-on merger as a merger of IXYS with and into a subsidiary of Littelfuse. As a result of the merger, IXYS will no longer be a publicly held company. Following the merger, IXYS common stock will be delisted from The NASDAQ Global Select Market and deregistered under the Exchange Act.

Q:    Will the Littelfuse common stock received at the time of completion of the merger be traded on an exchange?

A:
It is a condition to the consummation of the merger that the shares of Littelfuse common stock to be issued to IXYS stockholders in the merger be approved for listing on The NASDAQ Global Select Market, subject to official notice of issuance.

Q:    When is the merger expected to be completed?

A:
Littelfuse and IXYS currently expect the merger to be completed during the first quarter of calendar year 2018, subject to the affirmative vote of the holders of a majority of the outstanding shares of IXYS common stock in favor of adoption of the merger agreement and the satisfaction or waiver of the other conditions to closing contained in the merger agreement. However, Littelfuse and IXYS cannot predict the actual date on which the merger will be completed because completion is subject to conditions beyond their control and it is possible that such conditions could result in the merger being completed earlier or later or not being completed at all. See the sections titled "The Merger—Regulatory Approvals" beginning on page 83 and "The Merger Agreement—Conditions to Completion of the Merger" beginning on page 108.

Q:    What am I being asked to vote on?

A:
IXYS stockholders are being asked to vote upon the following proposals:

1.
Proposal 1—The Merger Proposal:    the proposal to adopt the merger agreement, which is further described in the sections titled "The Merger" beginning on page 49 and "The Merger Agreement" beginning on page 88 and a copy of which is attached to this proxy statement/prospectus as Annex A;

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    2.
    Proposal 2—The Merger-Related Compensation Proposal:    the proposal to approve on an advisory (non-binding) basis the compensation that may be paid or become payable to IXYS' named executive officers that is based on or otherwise relates to the merger; and

    3.
    Proposal 3—The Adjournment Proposal:    the proposal to approve the adjournment of the special meeting, if necessary, to solicit additional proxies if there are not sufficient votes to approve the merger proposal.

Q:    How does the IXYS board of directors recommend that I vote at the special meeting?

A:
The IXYS board of directors unanimously recommends that IXYS stockholders vote "FOR" the merger proposal and "FOR" each of the other proposals described in this proxy statement/prospectus.

Q:    What do I need to do now?

A:
After carefully reading and considering the information contained in this proxy statement/prospectus, please submit your proxy as soon as possible so that your shares of IXYS common stock will be represented and voted at the special meeting. Please follow the instructions set forth on the proxy card or on the voting instruction form provided by the record holder if your shares are held in "street name" by your bank, brokerage firm or other nominee.

Q:    Should I send in my IXYS stock certificates now?

A:
No. Please do not send in your IXYS stock certificates with your proxy. You should submit your IXYS stock certificates with your election form. Any IXYS stockholder who has not submitted its, his or her physical stock certificate(s) with a form of election will be sent materials after the merger closes to effect the exchange of such stockholder's IXYS common stock for the merger consideration. See "The Merger Agreement—Exchange and Payment Procedures."

Q:    When and where is the special meeting of the IXYS stockholders?

A:
The special meeting will be held on [    ·    ], 2017, beginning at [    ·    ], local time, at IXYS' principal executive offices at 1590 Buckeye Drive, Milpitas, California 95035, unless postponed to a later date.

Q:    Who can vote at the special meeting?

A:
Only IXYS stockholders who held shares of record as of the close of business on [    ·    ], 2017, the record date for the special meeting, are entitled to receive notice of and to vote at the special meeting. IXYS' official stock ownership records will conclusively determine whether a stockholder is a "holder of record" as of the record date.

Q:    How many votes do I have?

A:
Each IXYS stockholder is entitled to one vote on each matter properly brought before the special meeting for each share of IXYS common stock held of record as of the close of business on the record date. As of the close of business on the record date, there were [    ·    ] shares of IXYS common stock outstanding and owned by stockholders (i.e., excluding shares of IXYS common stock held in treasury by IXYS), held by [    ·    ] holders of record.

Q:    What constitutes a quorum for the special meeting?

A:
The presence at the special meeting, in person or by proxy, of the holders of a majority of the outstanding shares of IXYS common stock as of the record date entitled to vote at the special

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    meeting constitutes a quorum for the purposes of the special meeting. The Inspector of Elections at the special meeting will determine whether or not a quorum is present. Abstentions are considered present for purposes of establishing a quorum, but will not be counted as votes cast "FOR" any matter. Broker non-votes are considered present for purposes of establishing a quorum, but will not be counted as votes cast "FOR" any matter.

Q:    What vote is required to approve each proposal to be considered at the IXYS special meeting?

A:
The votes required for each proposal are as follows:

1.
The Merger Proposal:    The affirmative vote, in person or by proxy, of holders of a majority of the outstanding shares of IXYS common stock entitled to vote on the merger proposal is required to approve the merger proposal.

2.
The Merger-Related Compensation Proposal:    The affirmative vote of holders of a majority of the shares of IXYS common stock present in person or represented by proxy and entitled to vote on the merger-related compensation proposal is required to approve, on an advisory (non-binding) basis, the merger-related compensation proposal.

3.
The Adjournment Proposal:    The affirmative vote of holders of a majority of the shares of IXYS common stock present in person or represented by proxy and entitled to vote on the adjournment proposal is required to approve the adjournment proposal.

    As of [    ·    ], 2017, the record date, IXYS directors and executive officers, as a group, owned and were entitled to vote [    ·    ] shares of IXYS common stock, or approximately [    ·    ]% of the outstanding shares of IXYS common stock. IXYS currently expects that these directors and executive officers will vote their shares in favor of the merger proposal and each of the other proposals described in this proxy statement/prospectus, although none of them, other than Dr. Nathan Zommer, has entered into any agreement obligating them to do so.

    Concurrently with the execution of the merger agreement, each of Dr. Nathan Zommer (the current Chairman and Chief Executive Officer of IXYS) and certain of his controlled affiliates entered into a letter agreement with Littelfuse (referred to in this proxy statement/prospectus as the voting agreement) pursuant to which each party agreed, among other things, to vote the shares of IXYS common stock held by such party in favor of the merger proposal. See the section titled "The Voting Agreement" beginning on page 113.

    As of [    ·    ], 2017, the record date, approximately [    ·    ]% of the outstanding shares of IXYS common stock, were subject to the voting agreement, a copy of which is attached to this proxy statement/prospectus as Annex B.

Q:    How are proxies counted and what results from a failure to vote, abstention or broker non-vote?

A:
The Merger Proposal:    If you are an IXYS stockholder on the record date and take any action other than voting (or causing your shares to be voted) "FOR" the merger proposal, it will have the same effect as a vote "AGAINST" the merger proposal. For example, if you fail to instruct your bank, brokerage firm or other nominee to vote, it will have the same effect as a vote "AGAINST" the merger proposal.

    The Merger-Related Compensation Proposal:    If you are an IXYS stockholder on the record date and attend the IXYS special meeting in person but fail to vote, or you are a stockholder and mark your proxy or voting instructions to abstain, it will have the same effect as a vote "AGAINST" the merger-related compensation proposal. If you are an IXYS stockholder and fail to vote by not attending the IXYS special meeting, in person or by proxy, or you fail to instruct your bank,

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    brokerage firm or other nominee to vote, it will have no effect on the merger-related compensation proposal (assuming a quorum is present).

    The Adjournment Proposal:    If you are an IXYS stockholder on the record date and attend the IXYS special meeting in person but fail to vote, or you are a stockholder and mark your proxy or voting instructions to abstain, it will have the same effect as a vote "AGAINST" the adjournment proposal. If you are an IXYS stockholder and fail to vote by not attending the IXYS special meeting, in person or by proxy, or you fail to instruct your bank, brokerage firm or other nominee to vote, it will have no effect on the adjournment proposal (assuming a quorum is present).

Q:    What will happen if the merger-related compensation proposal is not approved?

A:
The merger-related compensation proposal is advisory only and not binding on IXYS or Littelfuse, whether or not the merger is completed. The vote on the merger-related compensation proposal is separate and apart from the vote to adopt the merger agreement and not a condition to the completion of the merger. If the merger is completed, the merger-related compensation that is the subject of this proposal may be paid to IXYS' named executive officers in accordance with the terms of their compensation agreements and arrangements even if the stockholders fail to approve this proposal.

Q:    How do I vote or have my shares voted?

A:
If you are an IXYS stockholder of record, you may vote in person at the special meeting or vote by proxy using the enclosed proxy card. Whether or not you plan to attend the meeting, we urge you to vote by proxy to ensure your vote is counted. You may still attend the meeting and vote in person even if you have already voted by proxy.

To vote in person, come to the special meeting and we will give you a ballot when you arrive.

To vote using the proxy card, simply complete, sign and date the enclosed proxy card and return it promptly in the envelope provided. If you return your signed proxy card to us before the special meeting, we will vote your shares as you direct.

To vote by telephone, submit your proxy by dialing the following number: [    ·    ]. Telephone voting is available 24 hours a day and will be accessible until [    ·    ], local time, on [    ·    ], 2017, the day before the special meeting.

To vote via the Internet, submit your proxy by going to the following website: [    ·    ]. Internet voting is available 24 hours a day and will be accessible until [    ·    ], local time, on [    ·    ], 2017, the day before the special meeting.

    If you are a beneficial owner of shares registered in the name of your bank, brokerage firm or other nominee, you should have received a proxy card and voting instructions with these proxy materials from that organization rather than from us. Simply complete and mail the proxy card to ensure that your vote is counted. To vote in person at the special meeting, you must obtain a valid proxy from your bank, brokerage firm or other nominee. Follow the instructions from the nominee included with these proxy materials, or contact the nominee to request a proxy form.

Q:    How will my proxy be voted?

A:
If you are a holder of record and submit your proxy via the Internet, by telephone or by completing, signing, dating and returning the enclosed proxy card, your shares will be voted in accordance with your instructions contained in the proxy. If you are a holder of record and submit your proxy without specifying how your shares should be voted in one or more matters, your shares will be voted on those matters as the IXYS board of directors recommends.

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    If you are a non-record owner, please refer to the instructions provided by your bank, brokerage firm or other nominee as to how to vote your shares.

Q:    What must I bring to attend the special meeting?

A:
Only stockholders of record as of the record date, non-record owners as of the record date, holders of valid proxies for the special meeting and invited guests of IXYS may attend the special meeting. All attendees should be prepared to present picture identification for admittance. The additional items, if any, that attendees must bring depend on whether they are stockholders of record, non-record owners or proxy holders.

    Additional information on attending the special meeting can be found under the section titled "Information About the IXYS Special Meeting" beginning on page 40. Whether or not you plan to attend the special meeting, IXYS urges you to submit your proxy by completing and returning the proxy card as promptly as possible, or by submitting your proxy by telephone or via the Internet prior to the special meeting to ensure that your shares of IXYS common stock will be represented and voted at the special meeting if you are unable to attend. If you are a non-record owner, please refer to the instructions provided by your bank, brokerage firm or other nominee to see which of the above choices are available to you. Please note that if you are a non-record owner and wish to vote in person at the special meeting, you must obtain a legal proxy from your bank, brokerage firm or other nominee.

Q:    If my shares are held in "street name" by my bank, brokerage firm or other nominee, will my bank, brokerage firm or other nominee vote my shares for me?

A:
No. If your shares are held in "street name" by your bank, brokerage firm or other nominee, you must direct your bank, brokerage firm or other nominee on how to vote and you will receive instructions from your bank, brokerage firm or other nominee describing how to vote your shares of IXYS common stock. The availability of Internet or telephonic voting will depend on the nominee's voting process. Please check with your bank, brokerage firm or other nominee and follow the voting procedures your bank, brokerage firm or other nominee provides.

    If you are a non-record owner and do not provide your bank, brokerage firm or other nominee instructions on how to vote your shares of IXYS common stock with respect to a "non-routine" matter, a broker "non-vote" occurs with respect to those matters. Under applicable stock exchange rules, the organization that holds your shares of IXYS common stock (i.e., your bank, brokerage firm or other nominee) may generally vote on routine matters at its discretion but cannot vote your shares on "non-routine" matters without your instructions. If you are a non-record owner and the organization that holds your shares of IXYS common stock does not receive instructions from you on how to vote your shares of IXYS common stock on a "non-routine" matter, the organization that holds your shares of IXYS common stock will inform the inspector of elections that it does not have the authority to vote your shares on such matters. The merger proposal, the merger-related compensation proposal and the adjournment proposal will be considered "non-routine." Accordingly, if you are a non-record owner and do not provide your bank, brokerage firm or other nominee instructions on how to vote your shares of IXYS common stock, your bank, brokerage firm or other nominee generally will not be permitted to vote your shares on any of the proposals at the special meeting. If you are a non-record owner, IXYS strongly encourages you to provide voting instructions to your bank, brokerage firm or other nominee so that your vote will be counted on all matters.

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Q:    What is the difference between holding shares as a stockholder of record and in "street name"?

A:
If your shares of IXYS common stock are registered directly in your name with the transfer agent of IXYS, Computershare Inc., you are considered the stockholder of record with respect to those shares. As the stockholder of record, you have the right to vote or to grant a proxy for your vote directly to IXYS or to a third party to vote at the special meeting.

    If your shares are held by a bank, brokerage firm or other nominee, you are considered the beneficial owner of shares held in "street name," and, for the purposes of this proxy statement/prospectus, a non-record owner, and your bank, brokerage firm or other nominee is considered the stockholder of record with respect to those shares. If you are a non-record owner, you have a right to direct your bank, brokerage firm or other nominee on how to vote the shares held in your account. The availability of Internet or telephonic voting will depend on the nominee's voting process. Please check with your bank, brokerage firm or other nominee and follow the voting procedures your bank, brokerage firm or other nominee provides. You are invited to attend the special meeting; however, you may not vote your shares in person at the special meeting unless you obtain a "legal proxy" from your bank, brokerage firm or other nominee that holds your shares, giving you the right to vote the shares at the special meeting.

Q:    What should I do if I receive more than one set of voting materials for the special meeting?

A:
You may receive more than one set of voting materials for the special meeting, including multiple copies of this proxy statement/prospectus and multiple proxy cards or voting instruction cards. For example, if you hold your IXYS common stock in more than one brokerage account, you will receive a separate voting instruction card for each brokerage account in which you hold shares. If you are a stockholder of record and your shares are registered in more than one name, you will receive more than one proxy card. Please submit each separate proxy or voting instruction card that you receive by following the instructions set forth in each separate proxy or voting instruction card.

Q:    What do I do if I am an IXYS stockholder and I want to revoke my proxy?

A:
IXYS stockholders of record may revoke their proxies at any time prior to the voting at the special meeting in any of the following ways:

submitting another properly completed proxy card with a later date;

sending timely written notice that you are revoking your proxy to IXYS Corporation's Secretary, Uzi Sasson, at 1590 Buckeye Drive, Milpitas, California 95035;

submitting a proxy via the Internet or by telephone at a later date but before the voting at the special meeting (in which case only the later-dated proxy is counted and the earlier proxy is revoked); or

attending the special meeting and voting in person. Attendance at the special meeting will not, however, in and of itself, constitute a vote or revocation of a prior proxy.

    IXYS non-record owners may change their voting instructions only by following the directions received from their bank, brokerage firm or other nominee for changing their voting instructions.

Q:    What happens if I sell my shares of IXYS common stock before the special meeting?

A:
The record date is earlier than both the date of the special meeting and the closing of the merger. If you transfer your shares of IXYS common stock after the record date but before the special meeting, you will, unless the transferee requests a proxy from you, retain your right to vote at the special meeting but will transfer the right to receive the merger consideration to the person to

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    whom you transfer your shares. In order to receive the merger consideration, you must hold your shares upon completion of the merger.

Q:    Do IXYS stockholders have appraisal rights?

A:
Yes. IXYS stockholders are entitled to appraisal rights under Section 262 of the General Corporation Law of the State of Delaware (referred to in this proxy statement/prospectus as the DGCL), provided they follow the procedures and satisfy the conditions set forth in Section 262 of the DGCL. For more information regarding appraisal rights, see the section titled "Appraisal Rights of IXYS Stockholders" beginning on page 142. In addition, a copy of Section 262 of the DGCL is attached as Annex D to this proxy statement/prospectus. Failure to strictly comply with Section 262 of the DGCL may result in your waiver of, or inability to, exercise appraisal rights.

Q:    Who will solicit and pay the cost of soliciting proxies?

A:
IXYS will pay for the proxy solicitation costs related to the special meeting. IXYS has engaged D.F. King to assist in the solicitation of proxies for the special meeting. IXYS estimates that it will pay D.F. King a fee of approximately $10,500, plus reasonable out-of-pocket expenses. IXYS will also reimburse banks, brokerage firms, custodians, trustees, nominees and fiduciaries who hold shares for the benefit of another party for their expenses incurred in sending proxies and proxy materials to non-record owners of IXYS common stock. IXYS' directors, officers and employees also may solicit proxies in person by telephone or over the Internet. They will not be paid any additional amounts for soliciting proxies.

Q:    How can I find more information about Littelfuse and IXYS?

A:
You can find more information about Littelfuse and IXYS from various sources described in the section titled "Where You Can Find More Information" beginning on page 150.

Q:    Who can answer any questions I may have about the special meeting or the proxy materials?

A:
If you have any questions about the special meeting, the merger, the proposals or this proxy statement/prospectus, would like additional copies of the proxy statement/prospectus, need to obtain proxy cards or other information related to this proxy solicitation or need help submitting a proxy or voting your shares of IXYS common stock, you should contact:

IXYS Corporation
1590 Buckeye Drive
Milpitas, CA 95035
(408) 457-9000
Attention: Investor Relations

or
D.F. King & Co., Inc.

48 Wall Street
New York, NY 10005

Banks and Brokerage Firms Call: (212) 493-3910
Stockholders Call Toll Free: (800) 334-0384
Email: ixys@dfking.com

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SUMMARY

        The following summary highlights selected information described in more detail elsewhere in this proxy statement/prospectus and the documents incorporated by reference into this proxy statement/prospectus, and may not contain all the information that may be important to you. To understand the merger and the matters being voted on by IXYS stockholders at the special meeting more fully, and to obtain a more complete description of the legal terms of the merger agreement, you should carefully read this entire proxy statement/prospectus, including the annexes, and the documents to which Littelfuse and IXYS refer you. Each item in this summary includes a page reference directing you to a more complete description of that topic. See the section titled "Where You Can Find More Information" beginning on page 150.

The Parties

        (see page 39)

IXYS Corporation

        IXYS Corporation, a Delaware corporation (referred to in this proxy statement/prospectus as IXYS), has been developing technology-driven products to improve energy conversion efficiency, generate clean energy, advance automation and provide solutions for the transportation, medical and telecommunication industries since its founding in Silicon Valley. IXYS, with its subsidiaries, has developed power semiconductors, solid state relays, high voltage integrated circuits and microcontrollers that are used in conserving energy and in reducing the world's dependence on fossil fuels. Diminishing natural resources, demand for renewable energy and environmental directives for energy efficiency represent a significant challenge. IXYS' power semiconductors and mixed-signal integrated circuits can reduce energy costs and consumption by improving the energy efficiency of everyday products. IXYS semiconductors are also used in medical devices and systems that provide diagnostics and therapy by medical equipment OEMs worldwide. IXYS common stock trades on The NASDAQ Global Select Market under the symbol "IXYS". The principal executive offices of IXYS are located at 1590 Buckeye Drive, Milpitas, California 95035, and its telephone number is (408) 457-9000.

Littelfuse, Inc.

        Littelfuse, Inc., a Delaware corporation (referred to in this proxy statement/prospectus as Littelfuse), is the world leader in circuit protection with growing global platforms in power control and sensing. The company serves customers in the electronics, automotive and industrial markets with technologies including fuses, semiconductors, polymers, ceramics, relays and sensors. Littelfuse has over 10,000 employees in more than 40 locations throughout the Americas, Europe and Asia. Littelfuse common stock trades on The NASDAQ Global Select Market under the symbol "LFUS". The principal executive offices of Littelfuse are located at 8755 West Higgins Road, Suite 500, Chicago, Illinois 60631, and its telephone number is (773) 628-1000.

Iron Merger Co., Inc.

        Iron Merger Co., Inc., a Delaware corporation (referred to in this proxy statement/prospectus as Merger Sub), is a wholly owned subsidiary of Littelfuse. Merger Sub was formed by Littelfuse solely in contemplation of the merger, has not conducted any business and has no assets, liabilities or obligations of any nature other than as set forth in the merger agreement. The principal executive offices of Merger Sub are located at c/o Littelfuse, Inc., 8755 West Higgins Road, Suite 500, Chicago, Illinois 60631, and its telephone number is (773) 628-1000.

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The Merger and the Merger Agreement

        (see pages 49 and 88)

        The terms and conditions of the merger are contained in the merger agreement, a copy of which is attached as Annex A to this proxy statement/prospectus. IXYS encourages you to read the merger agreement carefully and in its entirety, as it is the legal document that governs the merger.

        The merger agreement provides that, subject to the terms and conditions of the merger agreement, Merger Sub will merge with and into IXYS, with IXYS continuing as the surviving corporation in the initial merger and a wholly owned subsidiary of Littelfuse. Further to the terms of the merger agreement, IXYS, as the surviving corporation of the initial merger, will merge with and into Littelfuse (or a subsidiary of Littelfuse), with Littelfuse (or such subsidiary) continuing as the surviving corporation in the follow-on merger. Littelfuse intends to structure the follow-on merger as a merger of IXYS with and into a subsidiary of Littelfuse.

Merger Consideration

        (see page 49)

        At the effective time, each issued and outstanding share of IXYS common stock (other than shares (i) owned or held in treasury by IXYS or owned by Littelfuse or Merger Sub (referred to in this proxy statement/prospectus as cancelled shares) or (ii) owned by stockholders that did not vote in favor of the adoption of the merger agreement and have validly made a demand for appraisal and not validly withdrawn such demand or otherwise lost their rights of appraisal with respect to such shares pursuant to Section 262 of the DGCL) (referred to in this proxy statement/prospectus as dissenting shares) will be converted into the right to receive, at the election of the holder of such share and subject to proration, $23.00 in cash, less any applicable withholding taxes and without interest, or 0.1265 of a share of Littelfuse common stock. No fractional shares of Littelfuse common stock will be issued in the merger, and holders of IXYS common stock will instead receive cash in lieu of fractional shares of Littelfuse common stock.

        The merger consideration is subject to proration so that 50% of IXYS common stock issued and outstanding immediately prior to the effective time will be converted into cash consideration and the remaining IXYS common stock will be converted into stock consideration, based on an exchange ratio of 0.1265 of a share of Littelfuse common stock for each share of IXYS common stock entitled to receive stock consideration. A holder of IXYS common stock who does not make an election will be treated as having elected to receive cash consideration or stock consideration in accordance with the proration methodology in the merger agreement, which is described in the section titled "The Merger Agreement—Effect of the Merger on Capital Stock—Proration and Allocation of Merger Consideration" beginning on page 90.

        Based on the closing stock price of Littelfuse common stock on August 25, 2017, the last full trading day before the announcement of the merger, the per share value of IXYS common stock implied by the stock consideration is $22.55. Based on the closing stock price of Littelfuse common stock on [    ·    ], 2017, the most recent practicable date prior to the date of this proxy statement/prospectus, the per share value of IXYS common stock implied by the stock consideration is $[    ·    ]. The implied value of the stock consideration will fluctuate as the market price of Littelfuse common stock fluctuates because the stock consideration is payable in a fixed number of shares of Littelfuse common stock. As a result, the value of the stock consideration that IXYS stockholders will receive upon completion of the merger could be greater than, less than or the same as the value of the stock consideration on the date of this proxy statement/prospectus or at the time of the IXYS special meeting. Accordingly, Littelfuse and IXYS encourage you to obtain current stock price quotations for Littelfuse common stock and IXYS common stock before deciding how to vote with respect to approval

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of the merger proposal. Littelfuse common stock and IXYS common stock trade on The NASDAQ Global Select Market under the symbols "LFUS" and "IXYS," respectively.

IXYS Special Meeting

        (see page 40)

Purposes of the Special Meeting

        At the special meeting, IXYS stockholders will be asked to vote upon the following proposals:

    the merger proposal;

    the merger-related compensation proposal; and

    the adjournment proposal.

Record Date

        The record date for the determination of IXYS stockholders entitled to notice of and to vote at the special meeting is [    ·    ], 2017. Only IXYS stockholders who held shares of record as of the close of business on [    ·    ], 2017 are entitled to receive notice of and vote at the special meeting and any adjournment or postponement of the special meeting, as long as such shares remain outstanding on the date of the special meeting.

Required Vote

    The Merger Proposal:  The affirmative vote, in person or by proxy, of holders of a majority of the outstanding shares of IXYS common stock entitled to vote on the merger proposal is required to approve the merger proposal.

    The Merger-Related Compensation Proposal:  The affirmative vote of holders of a majority of the shares of IXYS common stock present in person or represented by proxy and entitled to vote on the merger-related compensation proposal is required to approve, on an advisory (non-binding) basis, the merger-related compensation proposal.

    The Adjournment Proposal:  The affirmative vote of holders of a majority of the shares of IXYS common stock present in person or represented by proxy and entitled to vote on the adjournment proposal is required to approve the adjournment proposal.

        As of [    ·    ], 2017, the record date, IXYS directors and executive officers, as a group, owned and were entitled to vote [    ·    ] shares of IXYS common stock, or approximately [    ·    ]% of the outstanding shares of IXYS common stock. IXYS currently expects that these directors and executive officers will vote their shares in favor of approving the merger proposal and each of the other proposals described in this proxy statement/prospectus, although none of them, other than Dr. Nathan Zommer, has entered into any agreement obligating them to do so.

        Concurrently with the execution of the merger agreement, each of Dr. Nathan Zommer (the current Chairman and Chief Executive Officer of IXYS) and certain of his controlled affiliates entered into the voting agreement with Littelfuse pursuant to which each party agreed, among other things, to vote the shares of IXYS common stock held by such party in favor of the merger proposal. See the section titled "The Voting Agreement" beginning on page 113.

        As of [    ·    ], 2017, the record date, approximately [    ·    ]% of the outstanding shares of IXYS common stock, were subject to the voting agreement, a copy of which is attached to this proxy statement/prospectus as Annex B.

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How Proxies Are Counted; Failure to Vote; Abstentions and Broker Non-Votes

        The Merger Proposal:    If you are an IXYS stockholder on the record date and take any action other than voting (or causing your shares to be voted) "FOR" the merger proposal, it will have the same effect as a vote "AGAINST" the merger proposal. For example, if you fail to instruct your bank, brokerage firm or other nominee to vote, it will have the same effect as a vote "AGAINST" the merger proposal.

        The Merger-Related Compensation Proposal:    If you are an IXYS stockholder on the record date and attend the IXYS special meeting in person but fail to vote, or you are a stockholder and mark your proxy or voting instructions to abstain, it will have the same effect as a vote "AGAINST" the merger-related compensation proposal. If you are an IXYS stockholder and fail to vote by not attending the IXYS special meeting, in person or by proxy, or you fail to instruct your bank, brokerage firm or other nominee to vote, it will have no effect on the merger-related compensation proposal (assuming a quorum is present).

        The Adjournment Proposal:    If you are an IXYS stockholder on the record date and attend the IXYS special meeting in person but fail to vote, or you are a stockholder and mark your proxy or voting instructions to abstain, it will have the same effect as a vote "AGAINST" the adjournment proposal. If you are an IXYS stockholder and fail to vote by not attending the IXYS special meeting, in person or by proxy, or you fail to instruct your bank, brokerage firm or other nominee to vote, it will have no effect on the adjournment proposal (assuming a quorum is present).

IXYS' Reasons for the Merger; Recommendation of the IXYS Board of Directors

        (see page 55)

        After careful evaluation of the merger agreement and the transactions contemplated thereby, the IXYS board of directors unanimously determined that the terms of the merger agreement and the merger are fair to, and in the best interests of, IXYS and its stockholders, and that it is in the best interests of IXYS and its stockholders, and declared it advisable, for IXYS to enter into the merger agreement.

        The IXYS board of directors unanimously recommends that IXYS stockholders vote "FOR" the merger proposal, and "FOR" each of the other proposals described in this proxy statement/prospectus.

        In the course of reaching its recommendation, the IXYS board of directors consulted with IXYS' senior management and financial advisor, Needham & Company, LLC (referred to in this proxy statement/prospectus as Needham & Company) and outside legal counsel and considered a number of factors. See the section titled "The Merger—IXYS' Reasons for the Merger; Recommendation of the IXYS Board of Directors" beginning on page 55.

Opinion of IXYS' Financial Advisor

        (see page 64)

        In connection with the merger, on August 25, 2017, Needham & Company delivered its oral opinion, which it subsequently confirmed in writing, that as of such date, and based upon and subject to the assumptions, qualifications, limitations and other matters set forth in its written opinion, the consideration of $23.00 in cash or 0.1265 of a share of Littelfuse common stock per share of IXYS common stock to be received by the holders of IXYS common stock (other than the holders of cancelled shares and dissenting shares) pursuant to the merger agreement was fair, from a financial point of view, to such holders.

        The full text of Needham & Company's written opinion, dated August 25, 2017, is attached as Annex C to this proxy statement/prospectus and is incorporated into this proxy statement/prospectus

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by reference. Needham & Company provided its opinion to the IXYS board of directors for the information and assistance of the IXYS board of directors (in its capacity as such) in connection with and for the purpose of the IXYS board of directors' evaluation of the transactions contemplated by the merger agreement. Needham & Company's opinion does not address any other aspect of the merger, or any related transaction, and does not constitute a recommendation to any stockholder of IXYS as to whether that stockholder should elect to receive the cash consideration or the stock consideration, or make no such election, or how that stockholder should vote or act on any matter relating to the merger.

Interests of IXYS' Directors and Executive Officers in the Merger

        (see page 74)

        When considering the recommendation of the IXYS board of directors with respect to the merger proposal and the merger-related compensation proposal, you should be aware that IXYS' directors and executive officers may have interests in the merger that are different from, or in addition to, those of IXYS stockholders more generally. The IXYS board of directors was aware of these interests during its deliberations on the merits of the merger and considered them in deciding to recommend that IXYS stockholders vote in favor of the merger proposal and the merger-related compensation proposal. These interests include, among others, the rights to accelerated vesting of stock options and certain payments and benefits in connection with the merger and/or a qualifying termination of employment following the merger, as described in more detail in the section titled "The Merger—Interests of IXYS' Directors and Executive Officers in the Merger" beginning on page 74.

Material U.S. Federal Income Tax Consequences

        (see page 79)

        The initial merger and the follow-on merger, taken together, are intended to qualify as a "reorganization" within the meaning of Section 368(a) of the Internal Revenue Code of 1986, as amended (referred to in this proxy statement/prospectus as the Code). The completion of the initial merger and the follow-on merger is conditioned upon the delivery by each of Wachtell, Lipton, Rosen & Katz (or other nationally recognized outside counsel), counsel to Littelfuse, and Latham & Watkins LLP (or other nationally recognized outside counsel), counsel to IXYS, of its opinion to the effect that the initial merger and the follow-on merger, taken together, will qualify as a "reorganization" within the meaning of Section 368(a) of the Code. If the initial merger and the follow-on merger, taken together, qualify as a "reorganization" within the meaning of Section 368(a) of the Code, the U.S. federal income tax consequences to IXYS stockholders who are U.S. holders (as defined in the section titled "Material U.S. Federal Income Tax Consequences") and receive stock consideration and/or cash consideration in exchange for their shares of IXYS common stock pursuant to the merger agreement generally will be as follows:

    if an IXYS stockholder receives solely cash consideration in exchange for such stockholder's shares of IXYS common stock, such stockholder generally will recognize gain or loss equal to the difference between the amount of cash consideration received and the stockholder's adjusted tax basis in the shares of IXYS common stock surrendered;

    if an IXYS stockholder receives solely stock consideration in exchange for such stockholder's shares of IXYS common stock, such stockholder generally will not recognize any gain or loss, except in respect of cash in lieu of a fractional share of Littelfuse common stock; and

    if an IXYS stockholder receives a combination of stock consideration and cash consideration (other than cash in lieu of a fractional share of Littelfuse common stock) pursuant to the merger, such stockholder generally will recognize gain (but not loss) in an amount equal to the

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      lesser of (1) the sum of the amount of cash consideration and the fair market value of the stock consideration received, minus such stockholder's adjusted tax basis in its shares of IXYS common stock surrendered and (2) the amount of cash consideration received.

        Each IXYS stockholder should read the discussion under the section titled "Material U.S. Federal Income Tax Consequences" and should consult his, her or its own tax advisor for a full understanding of the tax consequences of the merger to such stockholder.

Accounting Treatment of the Merger

        (see page 79)

        Littelfuse prepares its financial statements in accordance with accounting principles generally accepted in the United States of America (referred to in this proxy statement/prospectus as GAAP). The merger will be accounted for using the acquisition method of accounting. Littelfuse will be treated as the acquiror for accounting purposes.

Regulatory Approvals Required to Complete the Merger

        (see pages 83 and 109)

        Littelfuse, IXYS and Merger Sub have each agreed to use their respective reasonable best efforts to take, or cause to be taken, all reasonable actions, and to do, or cause to be done, all reasonable things necessary, proper or advisable under any applicable laws to consummate the merger and obtain (and to cooperate with each other in obtaining) the required regulatory approvals, as described in the section titled "The Merger—Regulatory Approvals" beginning on page 83.

        The obligations of Littelfuse and IXYS to consummate the merger were subject to, among other matters, the termination or expiration of the waiting period (and any extension thereof) applicable to the merger under the HSR Act and the receipt of the clearances and approvals applicable to the merger under the antitrust/merger control laws of Germany. On October 2, 2017, Littelfuse and IXYS received early termination of the applicable waiting period under the HSR Act in the United States, and on October 6, 2017, Littelfuse and IXYS received the required German clearance. There are no other known regulatory approvals required before the closing of the merger.

Expected Timing of Merger

        Littelfuse and IXYS currently expect the merger to be completed during the first quarter of calendar year 2018, subject to the affirmative vote of the holders of a majority of the outstanding shares of IXYS common stock in favor of adoption of the merger agreement and the satisfaction or waiver of the other conditions to closing contained in the merger agreement. However, Littelfuse and IXYS cannot predict the actual date on which the merger will be completed because completion is subject to conditions beyond their control and it is possible that such conditions could result in the merger being completed earlier or later or not being completed at all. See the sections titled "The Merger—Regulatory Approvals" beginning on page 83 and "The Merger Agreement—Conditions to Completion of the Merger" beginning on page 108.

Treatment of IXYS Stock Options

        (see pages 74 and 95)

        At the effective time, each outstanding and unexercised IXYS stock option will be assumed by Littelfuse and converted into a Littelfuse stock option to acquire (i) that number of whole shares of Littelfuse common stock (rounded down to the nearest whole share) equal to the product of (x) the number of shares of IXYS common stock subject to such IXYS stock option immediately prior to the

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effective time multiplied by (y) 0.1265, (ii) at an exercise price per share of Littelfuse common stock (rounded up to the nearest whole cent) equal to the quotient of (x) the exercise price per share of IXYS common stock of such IXYS stock option divided by (y) 0.1265. Each IXYS stock option assumed and converted into a Littelfuse stock option will continue to have, and will be subject to, the same vesting schedule (including any accelerated vesting terms) and all other terms and conditions as applied to such IXYS stock option immediately prior to the effective time.

Listing of Littelfuse Common Stock; Delisting of IXYS Common Stock

        (see page 87)

        It is a condition to the consummation of the merger that the shares of Littelfuse common stock to be issued to IXYS stockholders in the merger be approved for listing on The NASDAQ Global Select Market, subject to official notice of issuance. As a result of the merger, shares of IXYS common stock will cease to be listed on The NASDAQ Global Select Market.

Appraisal Rights

        (see page 142)

        IXYS stockholders who do not vote in favor of approval of the merger proposal, who continuously hold their shares of IXYS common stock through the effective time and who otherwise comply precisely with the applicable provisions of Section 262 of the DGCL will be entitled to seek appraisal of the fair value of their shares of IXYS common stock, as determined by the Delaware Court of Chancery, if the merger is completed. The "fair value" of your shares of IXYS common stock as determined by the Delaware Court of Chancery could be greater than, the same as, or less than the value of the merger consideration that you would otherwise be entitled to receive under the terms of the merger agreement. IXYS stockholders who wish to exercise the right to seek an appraisal of their shares must so advise IXYS by submitting a written demand for appraisal in the form described in this proxy statement/prospectus prior to the vote to approve the merger proposal, and must otherwise follow the procedures prescribed by Section 262 of the DGCL. A person having a beneficial interest in shares of IXYS common stock held of record in the name of another person, such as a nominee or intermediary, must act promptly to cause the record holder to follow the steps summarized in this proxy statement/prospectus and in a timely manner to perfect appraisal rights.

        The text of Section 262 of the DGCL is attached as Annex D to this proxy statement/prospectus. You are encouraged to read these provisions carefully and in their entirety. Due to the complexity of the procedures for exercising appraisal rights, IXYS stockholders who are considering exercising such rights are encouraged to seek the advice of legal counsel and their financial advisors. Failure to strictly comply with these provisions may result in the loss of appraisal rights.

No Solicitation of Company Takeover Proposals

        (see page 101)

        As more fully described in this proxy statement/prospectus and in the merger agreement, and subject to the exceptions summarized below, IXYS has agreed that it will not (1) solicit, initiate, knowingly encourage or knowingly facilitate any inquiry, proposal or offer that constitutes, or would reasonably be expected to lead to, a company takeover proposal (as defined on page 102), (2) engage in, continue or otherwise participate in any discussions or negotiations regarding any company takeover proposal, or (3) approve, recommend, or enter into, or propose to approve, recommend, or enter into, any agreement with respect to a company takeover proposal.

        Notwithstanding these restrictions, if at any time prior to obtaining the approval by IXYS stockholders of the merger proposal, IXYS receives a written, bona fide, unsolicited company takeover

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proposal that did not result from a breach of the merger agreement and that the IXYS board of directors determines in good faith (after consultation with its advisors) constitutes or would reasonably be expected to lead to a company superior proposal (as defined on page 102), IXYS may (1) furnish information with respect to IXYS to the party making the company takeover proposal (subject to certain conditions and obligations in the merger agreement) and (2) engage in discussions or negotiations with the party making the company takeover proposal.

        IXYS has agreed to notify Littelfuse within one business day of the receipt of any company takeover proposal or any request for information that is reasonably likely to lead to a company takeover proposal, or of any determination by the IXYS board of directors that a company takeover proposal constitutes or would be reasonably expected to lead to a company superior proposal. IXYS has also agreed to keep Littelfuse reasonably informed, on a reasonably current basis, as to the status of any company takeover proposal, and to promptly provide Littelfuse with any draft agreements relating to a company takeover proposal.

Changes in Board Recommendation

        (see page 103)

        The merger agreement provides that, subject to certain exceptions, the IXYS board of directors will not (i) fail to include its recommendation in favor of the merger proposal in this proxy statement/prospectus, (ii) change, qualify, withhold, withdraw or modify, or publicly propose to change, qualify, withhold, withdraw or modify (in each case in a manner adverse to Littelfuse) its recommendation in favor of the merger proposal, or (iii) adopt, approve or recommend to IXYS stockholders, or publicly propose or announce its intention to adopt, approve or recommend to IXYS stockholders, any company takeover proposal or agreement relating to a company takeover proposal (any of the foregoing, an adverse recommendation change). Notwithstanding these restrictions, at any time prior to obtaining the approval by IXYS stockholders of the merger proposal, the IXYS board of directors may, if it determines in good faith (after consultation with its advisors) that a company takeover proposal is a company superior proposal (and subject to compliance with certain obligations set forth in the merger agreement, including providing Littelfuse with prior notice and the right under certain circumstances to negotiate to match the terms of any company superior proposal), make an adverse recommendation change or terminate the merger agreement in order to enter into a binding agreement with respect to the company superior proposal.

        In addition, the IXYS board of directors is permitted under certain circumstances, prior to obtaining the approval by IXYS stockholders of the merger proposal and subject to compliance with certain obligations set forth in the merger agreement (including providing Littelfuse with prior notice and the right under certain circumstances to negotiate to amend the terms of the merger agreement) to make an adverse recommendation change in response to an intervening event (as defined on page 104) if the IXYS board of directors determines in good faith (after consultation with its advisors) that the failure to do so would be inconsistent with its fiduciary duties.

Conditions to Completion of the Merger

        (see page 108)

        The obligations of each of IXYS and Littelfuse to effect the merger are subject to the satisfaction or waiver of the following conditions:

    the approval by IXYS stockholders of the merger proposal;

    the SEC having declared effective the registration statement of which this proxy statement/prospectus forms a part;

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    the absence of any order, law or legal restraint by a court or other governmental entity of competent jurisdiction that prohibits, enjoins or makes illegal the closing of the merger;

    the expiration or termination of the waiting period (and any extensions thereof) applicable to the merger under the HSR Act and the receipt of the clearances and approvals applicable to the merger under the antitrust/merger control laws of Germany;

    the approval for listing by the NASDAQ Global Select Market of the shares of Littelfuse common stock to be issued to IXYS stockholders in the initial merger;

    the accuracy of the representations and warranties of the other party set forth in the merger agreement, subject to the materiality standards set forth in the merger agreement;

    the other party having performed, in all material respects, all obligations required to be performed by it under the merger agreement; and

    the receipt of a written tax opinion from each party's counsel in form and substance reasonably satisfactory to such party.

        In addition, Littelfuse's obligations to effect the merger are subject to IXYS' repayment of all of its outstanding debt obligations and delivery to Littelfuse of evidence of such repayment.

        Neither Littelfuse nor IXYS can be certain when, or if, the conditions to the merger will be satisfied or waived, or that the merger will be completed.

Termination of the Merger Agreement

        (see page 109)

        Littelfuse and IXYS may mutually agree to terminate the merger agreement before completing the merger, whether before or after the receipt of IXYS stockholder approval of the merger proposal.

        Either Littelfuse or IXYS may terminate the merger agreement, whether before or after the receipt of IXYS stockholder approval of the merger proposal:

    if the merger has not been consummated by February 28, 2018 (which deadline may be extended, under certain circumstances, to May 28, 2018);

    if IXYS stockholders fail to approve the merger proposal;

    if a court or other governmental entity issues a final, nonappealable order or adopts or enacts a law that in either case permanently restrains, enjoins or makes illegal the consummation of the merger; or

    if the other party breaches the merger agreement in a way that would entitle the party seeking to terminate the merger agreement not to consummate the merger, subject to the rights of the breaching party to cure the breach.

        IXYS may also terminate the merger agreement, prior to the receipt of IXYS stockholder approval of the merger proposal, in order to enter into an agreement for a company superior proposal, provided that IXYS has complied with its non-solicitation obligations under the merger agreement and pays a termination fee of $28.5 million to Littelfuse prior to or concurrently with such termination.

        Littelfuse may also terminate the merger agreement, prior to the receipt of IXYS stockholder approval of the merger proposal, if IXYS has made an adverse recommendation change or if IXYS is in willful breach of its non-solicitation obligations. Following such termination, IXYS must pay Littelfuse a termination fee of $28.5 million.

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Expenses and Termination Fees Relating to the Merger

        (see page 110)

        IXYS must pay Littelfuse a termination fee of $28.5 million if the merger agreement is terminated in certain circumstances involving a company takeover proposal, an adverse recommendation change or a willful breach of IXYS' non-solicitation obligations under the merger agreement.

        All other expenses relating to the merger will generally be paid by the party incurring the expense.

Comparison of Rights of Common Stockholders of Littelfuse and IXYS

        (see page 127)

        IXYS stockholders receiving shares of Littelfuse common stock in the initial merger will have different rights once they become stockholders of Littelfuse due to differences between the governing corporate documents applicable to IXYS and Littelfuse.

Risk Factors

        (see page 31)

        You should consider all the information contained in or incorporated by reference into this proxy statement/prospectus in deciding how to vote for the proposals presented in this proxy statement/prospectus.

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SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA

Selected Historical Consolidated Financial Data of Littelfuse

        The following selected historical consolidated financial data of Littelfuse for each of the fiscal years during the three-year period ended December 31, 2016 and the selected historical consolidated balance sheet data as of December 31, 2016 and January 2, 2016 have been derived from Littelfuse's audited consolidated financial statements as of and for the fiscal year ended December 31, 2016 contained in Littelfuse's Annual Report on Form 10-K for the fiscal year ended December 31, 2016, which is incorporated by reference into this proxy statement/prospectus. The selected historical consolidated financial data for each of the fiscal years ended December 28, 2013 and December 29, 2012 and the selected balance sheet data as of December 27, 2014, December 28, 2013 and December 29, 2012 have been derived from Littelfuse's audited consolidated financial statements as of and for such years contained in Littelfuse's other reports filed with the SEC, which are not incorporated by reference into this proxy statement/prospectus.

        The unaudited selected financial data for Littelfuse as of July 1, 2017, and for the six months ended July 1, 2017 and July 2, 2016, are derived from Littelfuse's unaudited condensed consolidated financial statements and accompanying notes, which are contained in Littelfuse's Quarterly Report on Form 10-Q for the quarter ended July 1, 2017, which is incorporated by reference into this proxy statement/prospectus. The selected financial data as of July 2, 2016 is derived from Littelfuse's unaudited condensed consolidated financial statements for the quarter ended July 2, 2016, which have previously been filed with the SEC but which are not incorporated by reference into this proxy statement/prospectus. The unaudited financial data presented have been prepared on a basis consistent with Littelfuse's audited consolidated financial statements. In the opinion of Littelfuse's management, such unaudited financial data reflect all adjustments, consisting only of normal and recurring adjustments, necessary for a fair presentation of the results for those periods. The results of operations for the interim periods are not necessarily indicative of the results to be expected for the full year or any future period.

        The information set forth below is only a summary and is not necessarily indicative of the results of future operations of Littelfuse, including following completion of the merger, and you should read the following information together with Littelfuse's consolidated financial statements, the related notes and the sections titled "Management's Discussion and Analysis of Financial Condition and Results of Operations" contained in Littelfuse's Annual Report on Form 10-K for the fiscal year ended December 31, 2016 and in its Quarterly Report on Form 10-Q for the quarter ended July 1, 2017, which are incorporated by reference into this proxy statement/prospectus, and in Littelfuse's other reports filed with the SEC. For more information, see the section titled "Where You Can Find More Information" beginning on page 150.

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LITTELFUSE, INC.
SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA
(Dollar Amounts in Thousands, Except Per Share Data)

 
  Six Months Ended or As
of
  Fiscal Years Ended  
 
  July 1, 2017   July 2, 2016   2016   2015   2014   2013   2012  
 
  (Unaudited)
  (Unaudited)
   
   
   
   
   
 

Net sales

  $ 598,797   $ 491,310   $ 1,056,159   $ 867,864   $ 851,995   $ 757,853   $ 667,913  

Gross profit

    246,258     185,021     413,117     330,499     324,428     296,232     258,467  

Operating income

    109,123     62,130     130,644     104,157     133,830     129,881     106,870  

Net income

    87,530     46,441     104,488     80,866     98,100     87,814     74,370  

Per share of common stock:

   
 
   
 
   
 
   
 
   
 
   
 
   
 
 

Income from continuing operations

                                           

Basic

    3.84     2.07     4.63     3.58     4.35     3.94     3.41  

Diluted

    3.80     2.05     4.60     3.56     4.32     3.90     3.37  

Cash dividends paid

    0.66     0.58     1.24     1.08     0.94     0.84     0.76  

Cash and cash equivalents

   
321,893
   
179,461
   
275,124
   
328,786
   
297,571
   
305,192
   
235,404
 

Total assets

    1,622,191     1,341,798     1,491,194     1,065,475     1,069,859     1,024,373     777,728  

Short-term debt

    7,813     6,250     6,250     87,000     88,500     126,000     84,000  

Long-term debt, less current portion

    473,879     361,732     447,892     83,753     105,691     93,750      

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Selected Historical Consolidated Financial Data of IXYS

        The following selected historical consolidated financial data of IXYS for the fiscal years ended March 31, 2017, March 31, 2016 and March 31, 2015 and the selected historical consolidated balance sheet data as of March 31, 2017 and March 31, 2016 have been derived from IXYS' audited consolidated financial statements contained in IXYS' Annual Report on Form 10-K for the fiscal year ended March 31, 2017, which is incorporated by reference into this proxy statement/prospectus. The selected historical consolidated financial data for the fiscal years ended March 31, 2014 and March 31, 2013 and the selected balance sheet data as of March 31, 2014, March 31, 2013 and March 31, 2012 have been derived from IXYS' audited consolidated financial statements as of and for such years, which statements are not incorporated by reference into this proxy statement/prospectus.

        The unaudited selected financial data for IXYS as of June 30, 2017, and for the three months ended June 30, 2017 and June 30, 2016, are derived from IXYS' unaudited condensed consolidated financial statements and accompanying notes, which are contained in IXYS' Quarterly Report on Form 10-Q for the quarter ended June 30, 2017, which is incorporated by reference into this proxy statement/prospectus. The selected financial data as of June 30, 2016 is derived from IXYS' unaudited condensed consolidated financial statements for the quarter ended June 30, 2016, which have previously been filed with the SEC but which are not incorporated by reference into this proxy statement/prospectus. The unaudited financial data presented have been prepared on a basis consistent with IXYS' audited consolidated financial statements. In the opinion of IXYS' management, such unaudited financial data reflect all adjustments, consisting only of normal and recurring adjustments, necessary for a fair presentation of the results for those periods. The results of operations for the interim periods are not necessarily indicative of the results to be expected for the full year or any future period.

        The information set forth below is only a summary and is not necessarily indicative of the results of future operations of IXYS, and you should read the following information together with IXYS' consolidated financial statements, the related notes and the sections titled "Management's Discussion and Analysis of Financial Condition and Results of Operations" contained in IXYS' Annual Report on Form 10-K for the fiscal year ended March 31, 2017, which is incorporated by reference into this proxy statement/prospectus, and in IXYS' other reports filed with the SEC. For more information, see the section titled "Where You Can Find More Information" beginning on page 150.

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IXYS CORPORATION
SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA
(Dollar Amounts in Thousands, Except Per Share Data)

 
  Three Months
Ended June 30
  Years Ended March 31,  
 
  2017   2016   2017   2016   2015   2014(1)   2013  
 
  (Unaudited)
   
   
   
   
   
 

Statement of operations data:

                                           

Net revenues

  $ 83,542   $ 80,638   $ 322,123   $ 317,209   $ 338,767   $ 336,330   $ 280,014  

Cost of goods sold

    56,996     56,644     216,541     217,451     236,802     236,120     195,134  

Gross profit

    26,546     23,994     105,582     99,758     101,965     100,210     84,880  

Operating expenses

                                           

Research, development and engineering

    7,573     7,910     30,538     29,986     26,667     30,884     28,022  

Selling, general and administrative

    10,006     10,038     41,733     38,384     41,810     41,983     39,287  

Amortization of acquisition-related intangible assets

    596     1,017     3,068     5,555     5,978     10,521     2,244  

Impairment of acquisition-related intangible assets

            1,391                  

Total operating expenses

    18,175     18,965     76,730     73,925     74,455     83,388     69,553  

Operating income

    8,371     5,029     28,852     25,833     27,510     16,822     15,327  

Other income (expense):

                                           

Interest income

    79     62     265     212     240     157     334  

Interest expense

    (694 )   (635 )   (2,545 )   (1,641 )   (1,397 )   (1,579 )   (938 )

Other income (expense), net

    (515 )   815     2,328     (915 )   4,077     (1,941 )   (41 )

Income before income tax provision

    7,241     5,271     28,900     23,489     30,430     13,459     14,682  

Provision for income tax

    (1,747 )   (2,252 )   (7,552 )   (8,748 )   (6,690 )   (7,413 )   (7,034 )

Net income

    5,494     3,019     21,348     14,741     23,740     6,046     7,648  

Net income per share:

                                           

Basic

    0.17     0.10     0.68     0.47     0.75     0.19     0.25  

Diluted

    0.17     0.09     0.66     0.46     0.74     0.19     0.24  

Cash dividends per common share

        0.040     0.040     0.155     0.135     0.120     0.060  

Weighted average shares used in per share calculation:

                                           

Basic

    32,086     31,401     31,544     31,579     31,531     31,146     31,025  

Diluted

    33,044     32,001     32,248     32,381     32,239     31,916     31,695  

(1)
During fiscal 2014, IXYS acquired a microcontroller product line from Samsung Electronics Co., Ltd.

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  Three Months Ended
June 30
  Years Ended March 31,  
 
  2017   2016   2017   2016   2015   2014(1)   2013  
 
  (Unaudited)
   
   
   
   
   
 

Balance sheet data:

                                           

Cash and cash equivalents

  $ 171,010   $ 151,393   $ 167,904   $ 155,806   $ 121,164   $ 98,438   $ 107,116  

Working capital

    278,258     245,489     266,000     253,820     169,096     177,684     188,111  

Total assets

    449,387     417,636     433,979     422,701     373,855     383,182     333,476  

Total long-term obligations

    99,002     100,757     98,310     108,896     27,760     43,204     31,640  

Total stockholders' equity

    315,216     279,956     297,855     279,295     267,301     270,632     253,608  

 

 
  Three Months
Ended June 30
  Years Ended March 31,  
 
  2017   2016   2017   2016   2015   2014(1)   2013  
 
  (Unaudited)
   
   
   
   
   
 

Cash flow data:

                                           

Cash provided by (used in) operating activities

    (417 ) $ 7,496   $ 34,537   $ 29,593   $ 48,194   $ 19,329   $ 31,637  

Cash used in investing activities(2)

    (4,347 )   (3,477 )   (11,193 )   (22,185 )   (15,148 )   (27,111 )   (11,277 )

Cash provided by (used in) financing activities

    4,934     (7,276 )   (6,998 )   25,977     (5,129 )   (3,344 )   (10,856 )

(1)
During fiscal 2014, IXYS acquired a microcontroller product line from Samsung Electronics Co., Ltd.

(2)
Cash used in investing activities has been restated in accordance with the amended guidance we adopted in fiscal 2017 which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and restricted cash. See Note 2, "Summary of Significant Accounting Policies" in the Notes to Consolidated Financial Statements in Item 8 of the IXYS Annual Report on Form 10-K for further information regarding the amended guidance.

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UNAUDITED COMPARATIVE PER SHARE INFORMATION

        The following tables summarize unaudited per share data for (i) Littelfuse on a historical basis for the fiscal year ended December 31, 2016 and the six months ended July 1, 2017; (ii) Littelfuse on a pro forma condensed combined basis, assuming that the merger occurred on the dates indicated; (iii) IXYS on a historical basis for the fiscal year ended March 31, 2017 and the three months ended June 30, 2017; and (iv) IXYS on a pro forma equivalent basis, which was calculated by multiplying the corresponding pro forma condensed combined data by the exchange ratio of 0.1265 of a share of Littelfuse common stock to 1.0 share of IXYS common stock. It has been assumed for purposes of the pro forma condensed combined financial information provided below that the pro forma events occurred on June 3, 2016 for earnings per share purposes and on July 1, 2017 for book value per share purposes.

        The historical earnings per share information should be read in conjunction with the historical consolidated financial statements and notes thereto of Littelfuse and IXYS incorporated by reference into this proxy statement/prospectus. See the section titled "Where You Can Find More Information" on page 150. The unaudited pro forma condensed combined earnings per share information is derived from, and should be read in conjunction with, the section titled "Unaudited Pro Forma Condensed Combined Financial Information" and related notes included in this proxy statement/prospectus beginning on page 114. The pro forma information is presented for illustrative purposes only and is not necessarily indicative of the operating results or financial position of Littelfuse following the merger.

 
  Littelfuse Twelve
Months Ended
December 31, 2016
  IXYS Twelve Months
Ended March 31, 2017
 
 
  Historical   Pro Forma
Condensed
Combined
  Historical   Pro Forma
Equivalent(1)
 

Basic earnings per share

  $ 4.63   $ 4.50   $ 0.68   $ 0.09  

Diluted earnings per share

    4.60     4.44     0.66     0.08  

Cash dividends per share(2)

    1.24     1.24     0.04     0.01  

Book value per share(3)

    36.02     N/A     9.33     N/A  

 

 
  Littelfuse Six Months
Ended July 1, 2017
  IXYS Three Months
Ended June 30, 2017
 
 
  Historical   Pro Forma
Condensed
Combined
  Historical   Pro Forma
Equivalent(1)
 

Basic earnings per share

  $ 3.84   $ 3.84   $ 0.17   $ 0.02  

Diluted earnings per share

    3.80     3.79     0.17     0.02  

Cash dividends per share(2)

    0.66     0.66          

Book value per share(3)

    39.42     57.90     9.67     1.22  

(1)
The pro forma equivalent share amounts were calculated by multiplying the pro forma condensed combined per share amounts by the exchange ratio of 0.1265 of a share of Littelfuse common stock per share of IXYS common stock. This information shows how each share of IXYS common stock would have participated in the combined company's net income and book value if the pro forma events had occurred on the relevant dates.

(2)
For the twelve months ended December 31, 2016 and the six months ended July 1, 2017, Littelfuse paid a cash dividend of $1.24 and $0.66 per share, respectively, to its stockholders. The pro forma dividends per share are based solely on Littelfuse's historical dividends.

(3)
Amount is calculated by dividing stockholders' equity by common shares outstanding at the end of the period.

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COMPARATIVE STOCK PRICE DATA AND DIVIDENDS

Stock Prices

        Littelfuse common stock trades on The NASDAQ Global Select Market under the symbol "LFUS." IXYS common stock trades on The NASDAQ Global Select Market under the symbol "IXYS."

        The following table sets forth the closing sales prices per share of Littelfuse common stock and IXYS common stock on The NASDAQ Global Select Market, and the implied value per share of one share of IXYS common stock, on the following dates:

    August 25, 2017, the last full trading day before the announcement of the merger, and

    [    ·    ], 2017, the last full trading day for which this information could be calculated before the date of this proxy statement/prospectus.
 
  Littelfuse
Common
Stock
  IXYS
Common
Stock
  Implied Value
Per Share of
Stock
Consideration(1)
 

August 25, 2017

  $ 178.26   $ 15.95   $ 22.55  

[·], 2017

    [·]     [·]     [·]  

(1)
The implied value per share of the stock consideration, as of each date, is equal to 0.1265, the exchange ratio for the stock consideration, multiplied by the closing market price of one share of Littelfuse common stock on such date.

        The following table sets forth, for the periods indicated, the high and low sales prices per share of Littelfuse common stock and of IXYS common stock as reported on The NASDAQ Global Select Market.

Littelfuse Common Stock

 
  Price Range    
 
 
  Cash
Dividends
 
 
  High   Low  

Fiscal Year ending December 30, 2017

                   

Fourth Quarter (through October 24, 2017)

  $ 212.47   $ 194.04     [·]  

Third Quarter

  $ 199.26   $ 161.65   $ 0.37  

Second Quarter

  $ 173.14   $ 149.81   $ 0.33  

First Quarter

  $ 167.21   $ 146.94   $ 0.33  

Fiscal Year ended December 31, 2016

                   

Fourth Quarter

  $ 156.54   $ 124.32   $ 0.33  

Third Quarter

  $ 130.79   $ 113.42   $ 0.33  

Second Quarter

  $ 123.15   $ 106.26   $ 0.29  

First Quarter

  $ 124.59   $ 90.61   $ 0.29  

Fiscal Year ended January 2, 2016

                   

Fourth Quarter

  $ 114.90   $ 87.32   $ 0.29  

Third Quarter

  $ 97.96   $ 82.53   $ 0.29  

Second Quarter

  $ 102.78   $ 93.31   $ 0.25  

First Quarter

  $ 103.08   $ 89.11   $ 0.25  

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IXYS Common Stock

 
  Price Range    
 
 
  Cash
Dividends
 
 
  High   Low  

Fiscal Year ending March 31, 2018

                   

Third Quarter (through October 24, 2017)

  $ 24.95   $ 23.58      

Second Quarter

  $ 23.95   $ 14.90      

First Quarter

  $ 16.95   $ 13.50      

Fiscal Year ended March 31, 2017

                   

Fourth Quarter

  $ 14.60   $ 11.10      

Third Quarter

  $ 12.25   $ 10.06      

Second Quarter

  $ 12.24   $ 10.08      

First Quarter

  $ 12.02   $ 9.59   $ 0.04  

Fiscal Year ended March 31, 2016

                   

Fourth Quarter

  $ 12.60   $ 10.03   $ 0.04  

Third Quarter

  $ 14.00   $ 10.84   $ 0.04  

Second Quarter

  $ 15.62   $ 10.00   $ 0.04  

First Quarter

  $ 16.76   $ 11.05   $ 0.035  

        As of [    ·    ], 2017, the last date before the date of this proxy statement/prospectus for which it was practicable to obtain this information, there were [    ·    ] shares of Littelfuse common stock outstanding and approximately [    ·    ] holders of record of Littelfuse common stock, and [    ·    ] shares of IXYS common stock outstanding and approximately [    ·    ] holders of record of IXYS common stock.

        Because the number of shares of Littelfuse common stock issuable for each share of IXYS Common Stock in the merger will not be adjusted for changes in the market price of either Littelfuse common stock or IXYS common stock, the market value of the shares of Littelfuse common stock that holders of IXYS common stock will have the right to receive on the date the merger is completed may vary significantly from the market value of the shares of Littelfuse common stock that holders of IXYS common stock would receive if the merger were completed on the date of this proxy statement/prospectus.

        As a result, you should obtain recent market prices of Littelfuse common stock and IXYS common stock prior to voting your shares. See the section titled "Risk Factors—Risks Relating to the Merger" beginning on page 31.

Dividends

        Littelfuse currently pays regular quarterly cash dividends on its common stock. Littelfuse most recently paid a cash dividend on September 7, 2017, of $0.37 per share. Littelfuse currently expects to continue to pay quarterly cash dividends, although they remain subject to determination and declaration by Littelfuse's board of directors. The payment of future dividends, if any, will be based on several factors, including Littelfuse's financial performance, outlook and liquidity.

        IXYS pays quarterly cash dividends on its common stock at the discretion of its board of directors. IXYS most recently paid a cash dividend on July 5, 2016 of $0.04 per share. The payment of future dividends, if any, will be based on IXYS' financial performance.

        Under the terms of the merger agreement, during the period before the closing of the merger, Littelfuse is not permitted to pay any dividends or make any distributions on its capital stock other than quarterly cash dividends not exceeding $0.37 per share, and IXYS is not permitted to pay any dividends or make any distributions on its capital stock, in each case without the consent of the other party.

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

        This proxy statement/prospectus and the documents incorporated by reference into this proxy statement/prospectus contain forward-looking statements within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995 that are not limited to historical facts but reflect Littelfuse's and IXYS' current beliefs, expectations or intentions regarding future events. Words such as "anticipate," "believe," "continue," "could," "estimate," "expect," "forecast," "guidance," "intend," "may," "plan," "possible," "potential," "predict," "project," "pursue," "will," "should," "target," and other similar words, phrases or expressions are intended to identify such forward-looking statements. These forward-looking statements include, without limitation, Littelfuse's and IXYS' expectations with respect to the synergies, costs and other anticipated financial impacts of the merger; future financial and operating results of the combined company; the combined company's plans, objectives, expectations and intentions with respect to future operations and services; required adoption of the merger agreement by IXYS stockholders; required approvals of the merger by governmental regulatory authorities; the satisfaction of the closing conditions to the merger; and the timing of the completion of the merger.

        All forward-looking statements involve significant risks and uncertainties that could cause actual results to differ materially from those expressed or implied in the forward-looking statements, many of which are generally outside the control of Littelfuse and IXYS and difficult to predict. These risks and uncertainties include, among others, those set forth under "Risk Factors" beginning on page 31, as well as risks and uncertainties relating to:

    the occurrence of any event, change or other circumstances that could give rise to the termination of the merger agreement or the failure to satisfy the closing conditions;

    the risk that the financing required to complete the merger is not obtained or is obtained on terms other than those currently anticipated;

    the possibility that the consummation of the merger is delayed or does not occur, including due to the failure of IXYS stockholders to approve the merger proposal;

    the ability to obtain the regulatory approvals required to complete the merger, and the timing and conditions for such approvals, including conditions that could reduce the expected synergies and other benefits of the merger, result in a material delay or the abandonment of the merger or otherwise have an adverse effect on Littelfuse;

    the taking of governmental action (including the passage of legislation) to block the merger or otherwise adversely affecting Littelfuse and IXYS;

    the outcome of any legal proceedings that have been or may be instituted against Littelfuse, IXYS or others following announcement of the merger;

    the possibility that the expected synergies from the merger will not be realized or will take longer to realize than expected;

    the ability of Littelfuse to successfully integrate the business of IXYS;

    unexpected costs or unexpected liabilities that may arise from the merger, whether or not consummated;

    the uncertainty of the value of the stock consideration that IXYS stockholders will receive in the initial merger due to a fixed exchange ratio and a potential fluctuation in the market price of Littelfuse common stock;

    IXYS' directors and executive officers having interests in the merger that are different from, or in addition to, the interests of IXYS stockholders more generally;

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    the possibility of changes in circumstances between the date of the signing of the merger agreement and the closing of the merger that are not reflected in the fairness opinion obtained by the IXYS board of directors;

    the effect of restrictions placed on Littelfuse's, IXYS' or their respective subsidiaries' business activities and the limitations put on IXYS' ability to pursue alternatives to the merger pursuant to the merger agreement;

    the disruption from the merger making it more difficult for Littelfuse and IXYS to maintain relationships with their respective customers, employees or suppliers;

    the response of activist stockholders to the merger;

    the inability of Littelfuse and IXYS to retain key personnel;

    the effect of the additional indebtedness that Littelfuse will incur in connection with the merger;

    the possibility of actual results of operations, cash flows and financial position after the merger materially differing from the unaudited pro forma condensed combined financial information contained in this proxy statement/prospectus; and

    the impact of global economic conditions, fluctuations in exchange rates, labor relations, competitive actions taken by other semiconductor businesses or other competitors, terrorist attacks or natural disasters.

        Littelfuse and IXYS caution that the foregoing list of factors is not exhaustive. Additional information concerning these and other risk factors is contained in Littelfuse's and IXYS' most recently filed Annual Reports on Form 10-K and subsequently filed Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other SEC filings, as such filings may be amended from time to time. All of the forward-looking statements made by Littelfuse or IXYS contained or incorporated by reference in this proxy statement/prospectus and all subsequent written and oral forward-looking statements concerning Littelfuse, IXYS, the merger or other matters attributable to Littelfuse or IXYS or any person acting on either of their behalf are expressly qualified in their entirety by the cautionary statement above.

        Readers are cautioned not to place undue reliance on forward-looking statements contained in this proxy statement/prospectus, which speak only as of the date such statements were made. Neither Littelfuse nor IXYS undertakes any obligation to update or revise any of these forward-looking statements to reflect events or circumstances that may arise after the date hereof, even if experience or future changes make it clear that projected results expressed or implied in such statements will not be realized, except as may be required by applicable law. Neither Littelfuse nor IXYS intends to make any update or other revision to forward-looking statements, except as may be required by applicable law.

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RISK FACTORS

        In addition to the other information included in and incorporated by reference into this proxy statement/prospectus, including the matters addressed in the section titled "Cautionary Statement Regarding Forward-Looking Statements" beginning on page 29, you should carefully consider the following risk factors before deciding whether to vote for the merger proposal and the other proposals described in this proxy statement/prospectus. In addition, you should read and consider the risk factors associated with each of the businesses of Littelfuse and IXYS because these risk factors will relate to the combined company following the completion of the merger. These risk factors may be found in Littelfuse's Annual Report on Form 10-K for the fiscal year ended December 31, 2016 and IXYS' Annual Report on Form 10-K for the fiscal year ended March 31, 2017 and, in each case, any amendments thereto, as such risk factors may be updated or supplemented in each company's subsequently filed Quarterly Reports on Form 10-Q or Current Reports on Form 8-K, which are incorporated by reference into this proxy statement/prospectus. You should also consider the other information in this proxy statement/prospectus and the other documents incorporated by reference into this proxy statement/prospectus. See the section titled "Where You Can Find More Information" beginning on page 150.

Risks Relating to the Merger

Because the share-election exchange ratio is fixed and will not be adjusted for stock price changes and the market price of Littelfuse common stock has fluctuated and will continue to fluctuate, IXYS stockholders cannot be sure of the value of the consideration they will receive.

        Upon completion of the initial merger, each issued and outstanding share of IXYS common stock (other than (i) cancelled shares or (ii) dissenting shares) will be converted into the right to receive, at the election of the stockholder and subject to proration, $23.00 in cash, without interest, less any applicable withholding taxes or 0.1265 of a share of Littelfuse common stock.

        The share-election ratio will not change to reflect changes in the market price of IXYS and Littelfuse common stock. The market price of Littelfuse common stock at the time of completion of the merger may vary significantly from the market price of Littelfuse common stock on the date the merger agreement was executed, the date of this proxy statement/prospectus and the date of the IXYS special meeting. In addition, as discussed below, the merger consideration will be subject to proration. Accordingly, IXYS stockholders will not know or be able to calculate at the time of the IXYS special meeting the market value of the stock consideration they will receive upon completion of the merger.

        In addition, the merger might not be completed until a significant period of time has passed after the IXYS special meeting. Because the share-election exchange ratio will not be adjusted to reflect any changes in the market values of Littelfuse common stock and IXYS common stock, the market value of the Littelfuse common stock issued in connection with the merger and the IXYS common stock surrendered in connection with the merger may be higher or lower than the value of those shares on earlier dates. Stock price changes may result from a variety of factors, including, among others, general market and economic conditions, changes in Littelfuse's and IXYS' respective businesses, operations and prospects, market assessments of the likelihood that the merger will be completed, the timing of the merger, regulatory considerations and other risk factors set forth or incorporated by reference in this proxy statement/prospectus. Many of these factors are beyond Littelfuse's and IXYS' control.

IXYS common stockholders may not receive all consideration in the form elected.

        IXYS common stockholders electing to receive either the all-cash consideration or the all-stock consideration in the merger will be subject to proration so that 50% of IXYS common stock issued and outstanding immediately prior to the effective time will be converted into cash consideration and the remaining IXYS common stock will be converted into stock consideration. Accordingly, some of the merger consideration an IXYS common stockholder receives may differ from the type of consideration

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selected and such difference may be significant. This may result in, among other things, tax consequences that differ from those that would have resulted if the IXYS common stockholder had received solely the form of consideration elected. A discussion of the proration mechanism can be found under the section titled "The Merger—Merger Consideration" and a discussion of the material U.S. federal income tax consequences of the merger can be found under the section titled "Material U.S. Federal Income Tax Consequences."

The market price of Littelfuse common stock after the initial merger will continue to fluctuate and may be affected by factors different from those affecting shares of IXYS common stock currently.

        Upon completion of the initial merger, certain holders of IXYS common stock will become holders of Littelfuse common stock. The market price of Littelfuse common stock may fluctuate significantly following completion of the initial merger and holders of IXYS common stock could lose the value of their investment in Littelfuse common stock. In addition, any significant price and volume fluctuations of the stock markets could have a material adverse effect on the market for, or liquidity of, the Littelfuse common stock, regardless of Littelfuse's actual operating performance. In addition, Littelfuse's business differs in important respects from that of IXYS, and accordingly, the results of operations of the combined company and the market price of Littelfuse common stock after the completion of the merger may be affected by factors different from those currently affecting the independent results of operations of each of Littelfuse and IXYS. For a discussion of the businesses of Littelfuse and IXYS and of some important factors to consider in connection with those businesses, see the documents incorporated by reference into this proxy statement/prospectus and referred to under "Where You Can Find More Information" beginning on page 150.

Sales of shares of Littelfuse common stock after the completion of the merger may cause the market price of Littelfuse common stock to fall.

        Based on the number of outstanding shares of IXYS common stock as of October 16, 2017, Littelfuse would issue approximately 2.1 million shares of Littelfuse common stock in the initial merger. Many IXYS stockholders may decide not to hold the shares of Littelfuse common stock they will receive in the initial merger. Other IXYS stockholders, such as funds with limitations on their permitted holdings of stock in individual issuers, may be required to sell the shares of Littelfuse common stock that they receive in the initial merger. Such sales of Littelfuse common stock could have the effect of depressing the market price for Littelfuse common stock and may take place promptly following the initial merger.

Completion of the merger is subject to the conditions contained in the merger agreement and if these conditions are not satisfied or waived, the merger will not be completed.

        The obligations of Littelfuse and IXYS to complete the merger are subject to the satisfaction or waiver of a number of conditions, including the approval of the merger proposal by IXYS stockholders. For a more complete summary of the required regulatory approvals and the conditions to the closing of the merger, see the sections titled "The Merger—Regulatory Approvals" and "The Merger Agreement—Conditions to Completion of the Merger."

        Many of the conditions to the closing of the merger are not within Littelfuse's or IXYS' control, and neither company can predict when or if these conditions will be satisfied. If any of these conditions are not satisfied or waived prior to February 28, 2018, which deadline may be extended to May 28, 2018 under certain circumstances, it is possible that the merger agreement will be terminated. Although Littelfuse and IXYS have agreed in the merger agreement to use their reasonable best efforts to complete the merger as soon as practicable, these and other conditions to the completion of the merger may not be satisfied. The failure to satisfy all of the required conditions could delay the completion of the merger for a significant period of time or prevent it from occurring. Any delay in completing the

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merger could cause Littelfuse not to realize some or all of the benefits that Littelfuse expects to achieve if the merger is successfully completed within its expected timeframe. There can be no assurance that the conditions to the closing of the merger will be satisfied or waived or that the merger will be completed. See the risk factor titled "—Failure to complete the merger could negatively affect the stock price and the future business and financial results of IXYS," below.

The merger was subject to the expiration of applicable waiting periods and the receipt of approvals, consents or clearances from regulatory authorities in the United States and Germany. Those clearances have been received, but the merger may still be reviewed under antitrust statutes of other governmental authorities.

        Littelfuse and IXYS received early termination of the applicable waiting period under the HSR Act in the United States on October 2, 2017, and on October 6, 2017, they received the requisite clearance under the antitrust/merger control laws of Germany. The merger may still be reviewed under antitrust statutes of other governmental authorities, including U.S. state laws. In deciding whether to grant the required regulatory approval, consent or clearance, the relevant governmental entities will consider the effect of the merger on competition within their relevant jurisdiction. The terms and conditions of the approvals, consents and clearances that are granted may impose requirements, limitations or costs or place restrictions on the conduct of the combined company's business. Under the merger agreement, Littelfuse and IXYS have agreed to use their reasonable best efforts to obtain such approvals, consents and clearances and therefore may be required to comply with conditions or limitations imposed by governmental authorities. There can be no assurance that other regulators will not impose conditions, terms, obligations or restrictions and that such conditions, terms, obligations or restrictions will not have the effect of delaying completion of the merger or imposing additional material costs on or materially limiting the revenues of the combined company following the completion of the merger. In addition, neither Littelfuse nor IXYS can provide assurance that any such conditions, terms, obligations or restrictions will not result in the delay or abandonment of the merger. See the sections titled "The Merger—Regulatory Approvals" and "The Merger Agreement—Conditions to Completion of the Merger" beginning on pages 83 and 108, respectively, of this proxy statement/prospectus.

Combining the two companies may be more difficult, costly or time consuming than expected and the anticipated benefits and cost savings of the merger may not be realized.

        IXYS and Littelfuse have operated and, until the completion of the merger, will continue to operate, independently. The success of the merger, including anticipated benefits and cost savings, will depend, in part, on Littelfuse's ability to successfully combine and integrate the businesses of Littelfuse and IXYS. It is possible that the pendency of the merger and/or the integration process could result in the loss of key employees, higher than expected costs, diversion of management attention of both IXYS and Littelfuse, the disruption of either company's ongoing businesses or inconsistencies in standards, controls, procedures and policies that adversely affect the combined company's ability to maintain relationships with customers, vendors and employees or to achieve the anticipated benefits and cost savings of the merger. As part of the integration process, Littelfuse may also attempt to divest certain assets of the combined company, which may not be possible on favorable terms, or at all, or if successful, may change the profile of the combined company. If Littelfuse experiences difficulties with the integration process, the anticipated benefits of the merger may not be realized fully or at all, or may take longer to realize than expected. Littelfuse's management continues to refine its integration plan. These integration matters could have an adverse effect on (i) each of Littelfuse and IXYS during this transition period and (ii) the combined company for an undetermined period after completion of the merger. In addition, the actual cost savings of the merger could be less than anticipated.

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IXYS' directors and executive officers have interests in the merger that may be different from, or in addition to, your interests as a stockholder of IXYS more generally.

        When considering the recommendation of the IXYS board of directors that IXYS stockholders approve the merger proposal and the merger-related compensation proposal, IXYS stockholders should be aware that directors and executive officers of IXYS have certain interests in the merger that may be different from, or in addition to, the interests of IXYS stockholders more generally. These interests generally include, among others, rights to accelerated vesting of stock options and certain payments and benefits in connection with the merger and/or a qualifying termination of employment following the merger. See the section titled "The Merger—Interests of IXYS' Directors and Executive Officers in the Merger" beginning on page 74 for a more detailed description of these interests. The IXYS board of directors was aware of these interests during its deliberations on the merits of the merger and considered them in deciding to recommend that IXYS stockholders vote in favor of the merger proposal and the merger-related compensation proposal.

The merger agreement limits IXYS' ability to pursue alternatives to the merger and may discourage other companies from trying to acquire IXYS.

        The merger agreement contains provisions that make it more difficult for IXYS to sell its business to a party other than Littelfuse. These provisions include a general prohibition on IXYS soliciting any company takeover proposal or offer for a competing transaction. Further, there are only limited exceptions to (i) IXYS' agreement that the IXYS board of directors will not withdraw or modify in a manner adverse to Littelfuse the recommendation of the IXYS board of directors that IXYS stockholders vote in favor of the merger proposal and (ii) IXYS' agreement not to enter into an agreement with respect to a competing company takeover proposal. In addition, upon termination of the merger agreement, IXYS is required to pay Littelfuse a termination fee of $28.5 million if the merger agreement is terminated in certain circumstances involving a company takeover proposal, an adverse recommendation change or a willful breach of IXYS' non-solicitation obligations under the merger agreement.

        These provisions could discourage a third party that might have an interest in acquiring all or a significant part of IXYS from considering or proposing that acquisition, even if that party were prepared to pay consideration with a higher per share value than the value proposed to be received or realized in the merger. These provisions might also result in a potential competing acquirer proposing to pay a lower price than it might otherwise have proposed to pay because of the added expense of the termination fee that may become payable in certain circumstances.

The merger agreement subjects IXYS to restrictions on its business activities.

        The merger agreement subjects IXYS to restrictions on its business activities and obligates IXYS to generally operate its businesses in all material respects in the ordinary course. These restrictions could have an adverse effect on IXYS' results of operations, cash flows and financial position.

The business relationships of Littelfuse and IXYS and their respective subsidiaries may be subject to disruption due to uncertainty associated with the merger, which could have an adverse effect on the results of operations, cash flows and financial position of Littelfuse, IXYS and, following the completion of the merger, the combined company.

        Parties with which Littelfuse and IXYS, or their respective subsidiaries, do business may be uncertain as to the effects on them of the merger and related transactions, including with respect to current or future business relationships with Littelfuse, IXYS, their respective subsidiaries or the combined company. These relationships may be subject to disruption as customers, suppliers and other persons with whom Littelfuse and IXYS have a business relationship may delay or defer certain

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business decisions or might decide to terminate, change or renegotiate their relationships with Littelfuse or IXYS, as applicable, or consider entering into business relationships with parties other than Littelfuse, IXYS, their respective subsidiaries or the combined company. These disruptions could have an adverse effect on the results of operations, cash flows and financial position of IXYS, Littelfuse or the combined company following the completion of the merger, including an adverse effect on Littelfuse's ability to realize the expected synergies and other benefits of the merger. The risk, and adverse effect, of any disruption could be exacerbated by a delay in completion of the merger or termination of the merger agreement.

Failure to complete the merger could negatively affect the stock price and the future business and financial results of IXYS.

        If the merger is not completed for any reason, including as a result of IXYS stockholders failing to approve the merger proposal, the ongoing business of IXYS may be adversely affected and, without realizing any of the benefits of having completed the merger, IXYS could be subject to a number of negative consequences, including the following:

    IXYS may experience negative reactions from the financial markets, including negative impacts on its stock price;

    IXYS may experience negative reactions from its customers and suppliers;

    IXYS may experience negative reactions from its employees and may not be able to retain key management personnel and other key employees;

    IXYS will have incurred, and will continue to incur, significant non-recurring costs in connection with the merger that it may be unable to recover;

    the merger agreement places certain restrictions on the conduct of IXYS' business prior to completion of the merger, the waiver of which is subject to the consent of Littelfuse (not to be unreasonably withheld, conditioned or delayed in certain circumstances), which may prevent IXYS from making certain acquisitions, taking certain other specified actions or otherwise pursuing business opportunities during the pendency of the merger that may be beneficial to IXYS (see the section titled "The Merger Agreement—Conduct of Businesses of IXYS and Littelfuse Prior to Completion of the Merger" beginning on page 98 for a description of the restrictive covenants applicable to IXYS); and

    matters relating to the merger (including integration planning) will require substantial commitments of time and resources by IXYS management, which could otherwise be devoted to day-to-day operations and other opportunities that may be beneficial to IXYS as an independent company.

        In addition, upon termination of the merger agreement, IXYS is required to pay Littelfuse a termination fee of $28.5 million if the merger agreement is terminated in certain circumstances involving a company takeover proposal, an adverse recommendation change or a willful breach of IXYS' non-solicitation obligations under the merger agreement. Finally, IXYS could be subject to litigation related to any failure to complete the merger or related to any enforcement proceeding commenced against IXYS to perform its obligations under the merger agreement. If the merger is not completed, any of these risks may materialize and may adversely affect IXYS' businesses, financial condition, financial results and stock price.

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The shares of Littelfuse common stock to be received by IXYS stockholders as a result of the merger will have rights different from the shares of IXYS common stock.

        Upon completion of the initial merger, IXYS stockholders will no longer be stockholders of IXYS. Former IXYS stockholders who receive stock consideration in the initial merger will become Littelfuse stockholders, and their rights as stockholders will be governed by the terms of the Littelfuse certificate of incorporation and bylaws and by the DGCL. See the section titled "Comparison of Rights of Common Stockholders of Littelfuse and IXYS" beginning on page 127 for a discussion of the different rights associated with Littelfuse common stock.

After the initial merger, IXYS stockholders will have a significantly lower ownership and voting interest in Littelfuse than they currently have in IXYS and will exercise less influence over management.

        Based on the number of shares of IXYS common stock outstanding as of October 16, 2017, and the number of shares of Littelfuse common stock outstanding as of October 16, 2017, it is expected that, immediately after completion of the initial merger, former IXYS stockholders will own approximately 8% of the outstanding shares of Littelfuse common stock. Consequently, former IXYS stockholders will have less influence over the management and policies of Littelfuse than they currently have over the management and policies of IXYS.

In connection with the merger, Littelfuse will incur new indebtedness, which could adversely affect Littelfuse, including by decreasing Littelfuse's business flexibility, and will increase its interest expense.

        Littelfuse's consolidated indebtedness as of July 1, 2017 was approximately $482 million. Littelfuse's pro forma indebtedness as of July 1, 2017, after giving effect to the merger and the anticipated incurrence of indebtedness in connection therewith, will be as much as $630 million. Littelfuse will have substantially increased indebtedness following completion of the merger in comparison to Littelfuse's indebtedness on a recent historical basis. In particular, in order to consummate the merger, Littelfuse expects to incur up to $150 million of new debt.

        This indebtedness could have the effect, among other things, of reducing Littelfuse's flexibility to respond to changing business and economic conditions and increasing Littelfuse's interest expense. The amount of cash required to pay interest on Littelfuse's increased indebtedness levels following completion of the merger, and thus the demands on Littelfuse's cash resources, will be greater than the amount of cash flows required to service the indebtedness of Littelfuse prior to the transaction. The cash resources required to service the increased levels of indebtedness following completion of the merger could also reduce funds available for working capital, capital expenditures, acquisitions and other general corporate purposes and may create competitive disadvantages for Littelfuse relative to other companies with lower debt levels. If Littelfuse does not achieve the expected benefits and cost savings from the merger, or if the financial performance of the combined company does not meet current expectations, then Littelfuse's ability to service its indebtedness may be adversely impacted.

        Certain of the indebtedness to be incurred in connection with the merger may bear interest at variable interest rates. If interest rates increase, variable rate debt will create higher debt service requirements, which could adversely affect Littelfuse's cash flows.

        Moreover, Littelfuse may be required to raise substantial additional financing to fund working capital, capital expenditures, acquisitions or other general corporate requirements. Littelfuse's ability to arrange additional financing or refinancing will depend on, among other factors, Littelfuse's financial position and performance, as well as prevailing market conditions and other factors beyond Littelfuse's control. Littelfuse cannot assure you that it will be able to obtain additional financing or refinancing on terms acceptable to Littelfuse or at all.

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The unaudited pro forma condensed combined financial information included in this proxy statement/prospectus is preliminary and the actual financial condition and results of operations after the merger may differ materially from them.

        The unaudited pro forma condensed combined financial information included in this proxy statement/prospectus is presented for illustrative purposes only and is not necessarily indicative of what Littelfuse's actual financial condition or results of operations would have been had the merger been completed on the dates indicated. The unaudited pro forma condensed combined financial information reflects adjustments, which are based upon assumptions, preliminary estimates and accounting reclassifications, to record the IXYS identifiable assets acquired and liabilities assumed at fair value and the resulting goodwill recognized. The purchase price allocation reflected in this proxy statement/prospectus is preliminary, and final allocation of the purchase price will be based upon the actual purchase price and the fair value of the assets and liabilities of IXYS as of the date of the completion of the merger. Accordingly, the final acquisition accounting adjustments may differ materially from the pro forma adjustments reflected in this proxy statement/prospectus. For more information, see the section titled "Unaudited Pro Forma Condensed Combined Financial Information" beginning on page 114.

The merger will involve substantial costs.

        IXYS and Littelfuse have incurred, and expect to continue to incur, a number of non-recurring costs associated with the merger and combining the operations of the two companies. The substantial majority of non-recurring expenses will be comprised of transaction costs related to the merger.

        Littelfuse also will incur transaction fees and costs related to formulating and implementing integration plans, including facilities and systems consolidation costs and employment-related costs. Littelfuse continues to assess the magnitude of these costs, and additional unanticipated costs may be incurred in the merger and the integration of the two companies' businesses. Although Littelfuse expects that the elimination of duplicative costs, as well as the realization of other efficiencies related to the integration of the businesses, should allow Littelfuse to offset integration-related costs over time, this net benefit may not be achieved in the near term, or at all. See the risk factor titled "—Combining the two companies may be more difficult, costly or time consuming than expected and the anticipated benefits and cost savings of the merger may not be realized" above.

Lawsuits may in the future be filed against IXYS, its directors, Littelfuse and Merger Sub challenging the merger, and an adverse ruling in any such lawsuit may prevent the merger from becoming effective or from becoming effective within the expected timeframe.

        Transactions like the merger are frequently the subject to litigation or other legal proceedings, including actions alleging that the board of directors of either IXYS or Littelfuse breached their respective fiduciary duties to their stockholders by entering into the merger agreement, by failing to obtain a greater value in the transaction for their stockholders or otherwise. Both IXYS and Littelfuse believe that any such litigation or proceedings would be without merit, but there can be no assurance that they will not be brought. If litigation or other legal proceedings are in fact brought against either IXYS or Littelfuse or against the board of directors of either company, they will defend against it, but they might not be successful in doing so. An adverse outcome in such matters, as well as the costs and efforts of a defense even if successful, could have a material adverse effect on the business, results of operation or financial position of IXYS, Littelfuse or the combined company, including through the possible diversion of either company's resources or distraction of key personnel.

        Further, one of the conditions to the completion of the merger is that no injunction by any court or other tribunal of competent jurisdiction will be in effect that temporarily or permanently prohibits, enjoins or makes illegal the consummation of the merger. As such, if any of the plaintiffs are successful

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in obtaining an injunction prohibiting the consummation of the merger, that injunction may prevent the merger from becoming effective or from becoming effective within the expected timeframe.

Uncertainties associated with the merger may cause a loss of management personnel and other key employees of IXYS or Littelfuse, which could adversely affect the future business and operations of the combined company following the merger.

        IXYS and Littelfuse are dependent on the experience and industry knowledge of their officers and other key employees to execute their business plans. The combined company's success after the merger will depend in part upon its ability to retain key management personnel and other key employees of IXYS and Littelfuse. Current and prospective employees of IXYS and Littelfuse may experience uncertainty about their future roles with the combined company following the merger, which may materially adversely affect the ability of each of IXYS and Littelfuse to attract and retain key personnel during the pendency of the merger. Accordingly, no assurance can be given that the combined company will be able to retain key management personnel and other key employees of IXYS and Littelfuse.

Other Risk Factors of Littelfuse and IXYS

        Littelfuse's and IXYS' businesses are and will be subject to the risks described above. In addition, Littelfuse and IXYS are, and will continue to be, subject to the risks described in Littelfuse's Annual Report for the fiscal year ended December 31, 2016 and IXYS' Annual Report on Form 10-K for the fiscal year ended March 31, 2017, as updated by subsequent Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, all of which are filed with the SEC and incorporated by reference into this proxy statement/prospectus. The risks described above and in those filings represent all known material risks with respect to Littelfuse's and IXYS' businesses. See the section titled "Where You Can Find More Information" beginning on page 150 for the location of information incorporated by reference into this proxy statement/prospectus.

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INFORMATION ABOUT IXYS

IXYS Corporation

        IXYS Corporation, a Delaware corporation (referred to in this proxy statement/prospectus as IXYS), has been developing technology-driven products to improve energy conversion efficiency, generate clean energy, advance automation and provide solutions for the transportation, medical and telecommunication industries since its founding in Silicon Valley. IXYS, with its subsidiaries, has developed power semiconductors, solid state relays, high voltage integrated circuits and microcontrollers that are used in conserving energy and in reducing the world's dependence on fossil fuels. Diminishing natural resources, demand for renewable energy and environmental directives for energy efficiency represent a significant challenge. IXYS' power semiconductors and mixed-signal integrated circuits can reduce energy costs and consumption by improving the energy efficiency of everyday products. IXYS semiconductors are also used in medical devices and systems that provide diagnostics and therapy by medical equipment OEMs worldwide. IXYS common stock trades on The NASDAQ Global Select Market under the symbol "IXYS". The principal executive offices of IXYS are located at 1590 Buckeye Drive, Milpitas, California 95035, and its telephone number is (408) 457-9000.


INFORMATION ABOUT LITTELFUSE

Littelfuse, Inc.

        Littelfuse, Inc., a Delaware corporation (referred to in this proxy statement/prospectus as Littelfuse), is the world leader in circuit protection with growing global platforms in power control and sensing. The company serves customers in the electronics, automotive and industrial markets with technologies including fuses, semiconductors, polymers, ceramics, relays and sensors. Littelfuse has over 10,000 employees in more than 40 locations throughout the Americas, Europe and Asia. Littelfuse common stock trades on The NASDAQ Global Select Market under the symbol "LFUS". The principal executive offices of Littelfuse are located at 8755 West Higgins Road, Suite 500, Chicago, Illinois 60631, and its telephone number is (773) 628-1000.

Iron Merger Co., Inc.

        Iron Merger Co., Inc., a Delaware corporation (referred to in this proxy statement/prospectus as Merger Sub), is a wholly owned subsidiary of Littelfuse. Merger Sub was formed by Littelfuse solely in contemplation of the merger, has not conducted any business and has no assets, liabilities or obligations of any nature other than as set forth in the merger agreement. The principal executive offices of Merger Sub are located at c/o Littelfuse, Inc., 8755 West Higgins Road, Suite 500, Chicago, Illinois 60631, and its telephone number is (773) 628-1000.

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INFORMATION ABOUT THE IXYS SPECIAL MEETING

General

        This proxy statement/prospectus is being provided to IXYS stockholders as part of a solicitation of proxies by the board of directors of IXYS for use at the special meeting of IXYS stockholders and at any adjournments or postponements of such special meeting. This proxy statement/prospectus provides IXYS stockholders with information about the special meeting and should be read carefully in its entirety.

Date, Time and Place of the Special Meeting

        The special meeting will be held on [    ·    ], 2017, beginning at [    ·    ], local time, at IXYS' principal executive offices at [    ·    ], unless postponed to a later date.

Purposes of the Special Meeting

        At the special meeting, IXYS stockholders will be asked to vote upon the following proposals:

    Proposal 1—The Merger Proposal:  the proposal to adopt the merger agreement, which is further described in the sections titled "The Merger" beginning on page 49 and "The Merger Agreement" beginning on page 88 and a copy of which is attached to this proxy statement/prospectus as Annex A;

    Proposal 2—The Merger-Related Compensation Proposal:  the proposal to approve on an advisory (non-binding) basis the compensation that may be paid or become payable to IXYS' named executive officers that is based on or otherwise relates to the merger; and

    Proposal 3—The Adjournment Proposal:  the proposal to approve the adjournment of the special meeting, if necessary, to solicit additional proxies if there are not sufficient votes to approve the merger proposal.

Only the approval of the merger proposal is required for completion of the merger.

Attendance at the Special Meeting

        Only IXYS stockholders of record as of the record date, non-record owners as of the record date, holders of valid proxies for the special meeting and invited guests of IXYS may attend the special meeting.

        All attendees should be prepared to present picture identification for admittance. The additional items, if any, that attendees must bring depend on whether they are stockholders of record, non-record owners or proxy holders.

    An IXYS stockholder who holds shares directly registered in such stockholder's name with IXYS' transfer agent, Computershare Inc. (referred to in this proxy statement/prospectus as a stockholder of record), who wishes to attend the special meeting in person should bring picture identification.

    A person who holds shares in "street name" through a bank, brokerage firm or other nominee (referred to in this proxy statement/prospectus as a non-record owner) who wishes to attend the special meeting in person should bring:

    picture identification; and

    a letter from such person's bank, brokerage firm or other nominee, or a current brokerage statement, to indicate that such bank, brokerage firm or other nominee is holding shares of IXYS common stock for such person's benefit.

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    A person who holds a validly executed proxy entitling such person to vote on behalf of a stockholder of record of IXYS shares (referred to in this proxy statement/prospectus as a proxy holder) who wishes to attend the special meeting in person should bring:

    picture identification;

    the validly executed proxy naming such person as the proxy holder, signed by the IXYS stockholder of record; and

    proof of the signing stockholder's record ownership as of the record date.

        Cameras, recording devices and other electronic devices, signs and placards will not be permitted at the special meeting. Failure to provide the requested documents at the door or failure to comply with the procedures for the special meeting may prevent stockholders of record, non-record owners or proxy holders from being admitted to the special meeting. IXYS reserves the right to request any person to leave the special meeting who is disruptive, refuses to follow the rules established for the special meeting or for any other reason.

Record Date

        The record date for the determination of stockholders entitled to notice of and to vote at the special meeting is [    ·    ], 2017. Only IXYS stockholders who held shares of record as of the close of business on [    ·    ], 2017 are entitled to receive notice of and vote at the special meeting and any adjournment or postponement of the special meeting, as long as such shares remain outstanding on the date of the special meeting. IXYS' official stock ownership records will conclusively determine whether a stockholder is a "holder of record" as of the record date.

Outstanding Shares As of Record Date

        As of [    ·    ], 2017, the record date for the special meeting, there were [    ·    ] shares of IXYS common stock outstanding and owned by stockholders (i.e., excluding shares of IXYS common stock held in treasury by IXYS), held by [    ·    ] holders of record. Each share of IXYS common stock is entitled to one vote on each matter considered at the special meeting.

        A list of IXYS stockholders entitled to vote at the special meeting will be available at the special meeting and for ten days prior to the special meeting between the hours of 9:00 a.m. and 5:00 p.m., local time, at IXYS' corporate headquarters at 1590 Buckeye Drive, Milpitas, California 95035.

Shares and Voting of IXYS' Directors and Executive Officers

        As of [    ·    ], 2017, the record date, IXYS directors and executive officers, as a group, owned and were entitled to vote [    ·    ] shares of IXYS common stock, or approximately [    ·    ]% of the outstanding shares of IXYS common stock. IXYS currently expects that these directors and executive officers will vote their shares in favor of the merger proposal and each of the other proposals described in this proxy statement/prospectus, although none of them, other than Dr. Nathan Zommer, has entered into any agreement obligating them to do so.

        Concurrently with the execution of the merger agreement, each of Dr. Nathan Zommer (the current Chairman and Chief Executive Officer of IXYS) and certain of his controlled affiliates entered into the voting agreement with Littelfuse pursuant to which each party agreed, among other things, to vote the shares of IXYS common stock held by such party in favor of the merger proposal. See the section titled "The Voting Agreement" beginning on page 113.

        As of [    ·    ], 2017, the record date, approximately [    ·    ]% of the outstanding shares of IXYS common stock, were subject to the voting agreement, a copy of which is attached to this proxy statement/prospectus as Annex B.

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Quorum and Broker Non-Votes

        In order for IXYS to transact business at the special meeting, the holders of a majority of the outstanding shares of IXYS common stock entitled to vote at the meeting must be present in person or represented by proxy. Stockholders choosing to abstain from voting will be treated as present for purposes of determining whether a quorum is present, but will not be counted as votes cast "FOR" any matter.

        Banks, brokerage firms and other nominees who hold shares for the accounts of their clients may vote such shares either as directed by their clients or in their own discretion on "routine" matters. When a broker does not receive instructions from a non-record owner on how to vote shares with respect to a "non-routine" matter, a broker "non-vote" occurs. Broker "non-votes" will be treated as present for purposes of determining whether a quorum is present, but will not be counted as votes cast "FOR" any matter.

Required Vote

        The votes required for each proposal are as follows:

        The Merger Proposal.    The affirmative vote, in person or by proxy, of holders of a majority of the outstanding shares of IXYS common stock entitled to vote on the merger proposal is required to approve the merger proposal. If you are an IXYS stockholder on the record date and take any action other than voting (or causing your shares to be voted) "FOR" the merger proposal, it will have the same effect as a vote "AGAINST" the merger proposal. For example, if you fail to instruct your bank, brokerage firm or other nominee to vote, it will have the same effect as a vote "AGAINST" the merger proposal.

        The Merger-Related Compensation Proposal.    The affirmative vote of holders of a majority of the shares of IXYS common stock present in person or represented by proxy and entitled to vote on the merger-related compensation proposal is required to approve, on an advisory (non-binding) basis, the merger-related compensation proposal. If you are an IXYS stockholder on the record date and attend the IXYS special meeting in person but fail to vote, or you are a stockholder and mark your proxy or voting instructions to abstain, it will have the same effect as a vote "AGAINST" the merger-related compensation proposal. If you are an IXYS stockholder and fail to vote by not attending the IXYS special meeting, in person or by proxy, or you fail to instruct your bank, brokerage firm or other nominee to vote, it will have no effect on the merger-related compensation proposal (assuming a quorum is present).

        The Adjournment Proposal.    The affirmative vote of holders of a majority of the shares of IXYS common stock present in person or represented by proxy and entitled to vote on the adjournment proposal is required to approve the adjournment proposal. If you are an IXYS stockholder on the record date and attend the IXYS special meeting in person but fail to vote, or you are a stockholder and mark your proxy or voting instructions to abstain, it will have the same effect as a vote "AGAINST" the adjournment proposal. If you are an IXYS stockholder and fail to vote by not attending the IXYS special meeting, in person or by proxy, or you fail to instruct your bank, brokerage firm or other nominee to vote, it will have no effect on the adjournment proposal (assuming a quorum is present).

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How To Vote or Have Your Shares Voted

        IXYS stockholders of record may vote their shares of IXYS common stock or submit a proxy to have their shares of IXYS common stock voted at the special meeting in one of the following ways:

    Internet:  IXYS stockholders may submit their proxy by using the Internet at www.[    ·    ].com. Internet voting is available 24 hours a day and will be accessible until [    ·    ], local time, on [    ·    ], 2017, the day before the special meeting.

    Telephone:  IXYS stockholders may submit their proxy by using a touch-tone telephone at [    ·    ]. Telephone voting is available 24 hours a day and will be accessible until [    ·    ], local time, on [    ·    ], 2017, the day before the special meeting.

    Mail:  IXYS stockholders may submit their proxy by properly completing, signing, dating and mailing their proxy card in the postage-paid envelope (if mailed in the United States) included with this proxy statement/prospectus. IXYS stockholders who vote this way should mail the proxy card early enough so that it is received before the date of the special meeting.

    In Person:  IXYS stockholders may vote in person at the special meeting or by sending a representative with an acceptable proxy that has been signed and dated. Attendance at the special meeting will not, however, in and of itself constitute a vote.

        Whether or not you plan to attend the special meeting, IXYS urges you to submit your proxy by completing and returning the proxy card as promptly as possible, or by submitting your proxy by telephone or via the Internet, prior to the special meeting to ensure that your shares of IXYS common stock will be represented and voted at the special meeting if you are unable to attend.

        The IXYS board of directors has appointed certain persons as proxy holders to vote proxies in accordance with the instructions of IXYS stockholders. If you are a stockholder of record and you authorize these proxy holders to vote your shares of IXYS common stock with respect to any matter to be acted upon, your shares will be voted in accordance with your instructions in your proxy. If you are a stockholder of record and you authorize these proxy holders to vote your shares but do not specify how your shares should be voted in one or more matters, these proxy holders will vote your shares on those matters as the IXYS board of directors recommends, except if you indicate that you wish to vote against the merger proposal, in which case your shares of IXYS common stock will only be voted in favor of the merger-related compensation proposal and the adjournment proposal if you indicate that you wish to vote in favor of such proposals. If any other matter properly comes before the special meeting, these proxy holders will vote on that matter in their discretion.

        If you are a non-record owner, you must direct your bank, brokerage firm or other nominee on how to vote the shares of IXYS common stock held in your account and you will receive instructions from your bank, brokerage firm or other nominee describing how to vote your shares of IXYS common stock. The availability of Internet or telephonic voting will depend on the nominee's voting process. Please check with your bank, brokerage firm or other nominee and follow the voting procedures your bank, brokerage firm or other nominee provides.

        If you are a non-record owner and do not provide your bank, brokerage firm or other nominee instructions on how to vote your shares of IXYS common stock with respect to "non-routine" matters, a broker "non-vote" occurs with respect to those matters. Under applicable stock exchange rules, the organization that holds your shares of IXYS common stock (i.e., your bank, brokerage firm or other nominee) may generally vote on routine matters at its discretion but cannot vote your shares on "non-routine" matters without your instructions. If you are a non-record owner and the organization that holds your shares of IXYS common stock does not receive instructions from you on how to vote your shares of IXYS common stock on a non-routine matter, the organization that holds your shares of IXYS common stock will inform the inspector of elections that it does not have the authority to vote

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your shares on such matters. The merger proposal, the merger-related compensation proposal and the adjournment proposal will be considered "non-routine." Accordingly, if you are a non-record owner and do not provide your bank, brokerage firm or other nominee instructions on how to vote your shares of IXYS common stock, your bank, brokerage firm or other nominee generally will not be permitted to vote your shares on any of the proposals. If you are a non-record holder, IXYS strongly encourages you to provide voting instructions to your bank, brokerage firm or other nominee so that your vote will be counted on all matters.

        If you are a non-record owner, you are invited to attend the special meeting; however, you may not vote your shares in person at the special meeting unless you obtain a legal proxy from your bank, brokerage firm or other nominee that holds your shares, giving you the right to vote the shares at the special meeting.

Revocation of Proxies

        IXYS stockholders of record may revoke their proxies at any time prior to the voting at the special meeting in any of the following ways:

    submitting another properly completed proxy card with a later date;

    sending timely written notice that you are revoking your proxy to IXYS Corporation's Secretary, Uzi Sasson, at 1590 Buckeye Drive, Milpitas, California 95035;

    submitting a proxy via Internet or by telephone at a later date (in which case only the later-dated proxy is counted and the earlier proxy is revoked); or

    attending the special meeting and voting in person. Attendance at the special meeting will not, however, in and of itself, constitute a vote or revocation of a prior proxy.

        IXYS non-record owners may change their voting instruction only by following the directions received from their bank, brokerage firm or other nominee for changing their voting instructions.

Solicitation of Proxies

        IXYS will pay for the proxy solicitation costs related to the special meeting. In addition to sending and making available these materials, some of IXYS' directors, officers and employees may solicit proxies in person by contacting IXYS stockholders by telephone or over the Internet. IXYS stockholders may also be solicited by press releases issued by IXYS, postings on IXYS' websites and advertisements in periodicals. None of IXYS' directors, officers or employees will receive additional compensation for their solicitation services. IXYS has engaged D.F. King to assist in the solicitation of proxies for the special meeting. IXYS estimates that it will pay D.F. King a fee of approximately $10,500, plus reasonable out-of-pocket expenses. Certain banking institutions, brokerage firms, custodians, trustees, nominees and fiduciaries who hold shares for the benefit of another party may solicit proxies for IXYS. If so, they will mail proxy information to, or otherwise communicate with, the non-record owners of shares of IXYS common stock held by them. IXYS will also reimburse banks, brokerage firms, custodians, trustees, nominees and fiduciaries for their expenses incurred in sending proxies and proxy materials to non-record owners of IXYS common stock.

Adjournments

        The special meeting may be adjourned in the absence of a quorum by the affirmative vote of holders of a majority of the shares of IXYS common stock present in person or represented by proxy and entitled to vote on the adjournment.

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        Even if a quorum is present, the special meeting may also be adjourned in order to provide more time to solicit additional proxies in favor of approval of the merger proposal if sufficient votes are cast in favor of the adjournment proposal.

        If the adjournment is for more than 30 days or if after the adjournment a new record date is set for the adjourned meeting, a notice of the adjourned meeting must be given to each stockholder of record entitled to vote at the special meeting.

Questions and Additional Information

        You may contact IXYS' proxy solicitor, D.F. King & Co., Inc., 48 Wall Street, New York, New York 10005, with any questions about the special meeting, the merger, the proposals or this proxy statement/prospectus, if you would like additional copies of the proxy statement/prospectus, if you need to obtain proxy cards or other information related to the proxy solicitation or if you need help submitting a proxy or voting your shares of IXYS common stock. Stockholders may call toll-free at (800) 334-0384, and banks and brokers may call collect at (212) 493-3910.

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PROPOSAL 1: THE MERGER PROPOSAL

        As discussed throughout this proxy statement/prospectus, IXYS is asking its stockholders to approve the merger proposal. Pursuant to the merger agreement, Littelfuse will acquire IXYS in the merger. Merger Sub will merge with and into IXYS, with IXYS continuing as the surviving corporation in the initial merger and a wholly owned subsidiary of Littelfuse. Further to the terms of the merger agreement, IXYS, as the surviving corporation of the initial merger, will merge with and into Littelfuse (or a subsidiary of Littelfuse), with Littelfuse (or such subsidiary) continuing as the surviving corporation in the follow-on merger. Littelfuse intends to structure the follow-on merger as a merger of IXYS with and into a subsidiary of Littelfuse. If the merger is completed, IXYS will cease to be publicly traded and IXYS common stock will be delisted from The NASDAQ Global Select Market and deregistered under the Exchange Act.

        As described in further detail in the sections titled "Questions and Answers" beginning on page 1, "Summary" beginning on page 11, "The Merger" beginning on page 49 and "The Merger Agreement" beginning on page 88, the IXYS board of directors has unanimously approved the merger agreement and the merger. For a discussion of certain factors considered by the IXYS board of directors in determining to approve the merger agreement and recommend that IXYS stockholders vote for the merger proposal, see the section titled "The Merger—IXYS' Reasons for the Merger; Recommendation of the IXYS Board of Directors" beginning on page 55. A copy of the merger agreement is attached as Annex A to this proxy statement/prospectus. You are urged to read the merger agreement carefully and in its entirety.

        The merger is subject to the satisfaction of the conditions set forth in the merger agreement, including approval of the merger proposal by the stockholders of IXYS at the special meeting. Accordingly, the approval of the merger proposal by IXYS stockholders is a condition to the obligations of Littelfuse and IXYS to complete the merger.

        The affirmative vote, in person or by proxy, of the holders of a majority of the outstanding shares of IXYS common stock entitled to vote on the merger proposal is required to approve the merger proposal.

        THE IXYS BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT IXYS STOCKHOLDERS VOTE "FOR" THE MERGER PROPOSAL.

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PROPOSAL 2: THE MERGER-RELATED COMPENSATION PROPOSAL

        IXYS is providing its stockholders with the opportunity to cast a vote, on an advisory (non-binding) basis, to approve the compensation payments that may be paid or become payable by IXYS to its named executive officers, as determined in accordance with Item 402(t) of Regulation S-K, in connection with the merger as disclosed in the section titled "Quantification of Potential Payments and Benefits to IXYS' Named Executive Officers in Connection with the Merger," including the table titled "Golden Parachute Compensation" and the accompanying footnotes, under "The Merger—Interests of IXYS' Directors and Executive Officers in the Merger" beginning on page 74 (referred to in this section of the proxy statement/prospectus as the "golden parachute" compensation), as required by Section 14A of the Exchange Act.

        Through this proposal, IXYS is asking its stockholders to indicate their approval, on an advisory (non-binding) basis, of the compensation that IXYS' named executive officers will or may be eligible to receive in connection with the merger as described in the section "Quantification of Potential Payments and Benefits to IXYS' Named Executive Officers in Connection with the Merger" referred to above.

        You should carefully review the "golden parachute" compensation information disclosed in the sections of this proxy statement/prospectus referred to above. The IXYS board of directors unanimously recommends that IXYS stockholders approve the following resolution:

        RESOLVED, that the stockholders of IXYS approve, solely on an advisory, non-binding basis, the "golden parachute" compensation that will or may be paid or become payable to IXYS' named executive officers in connection with the merger, as disclosed pursuant to Item 402(t) of Regulation S-K in the section titled "Quantification of Potential Payments and Benefits to IXYS' Named Executive Officers in Connection with the Merger," including the table titled "Golden Parachute Compensation" and the accompanying footnotes, under "The Merger—Interests of IXYS' Directors and Executive Officers in the Merger" beginning on page 74.

        The vote on the merger-related compensation proposal is a vote separate and apart from the vote on the merger proposal. Accordingly, you may vote to approve the merger proposal and vote not to approve the merger-related compensation proposal and vice versa. Because the vote on the merger-related compensation proposal is advisory only, it will not be binding on either IXYS or Littelfuse. Accordingly, if the merger proposal is approved and the merger is completed, the compensation payments that are contractually required to be paid by IXYS to its named executive officers will or may be paid or become payable, subject only to the conditions applicable thereto, regardless of the outcome of the non-binding, advisory vote of IXYS stockholders on the merger-related compensation proposal.

        The affirmative vote of holders of a majority of the shares of IXYS common stock present in person or represented by proxy and entitled to vote on the merger-related compensation proposal at the special meeting is required to approve, on an advisory (non-binding) basis, the merger-related compensation proposal.

        THE IXYS BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT IXYS STOCKHOLDERS VOTE "FOR" THE MERGER-RELATED COMPENSATION PROPOSAL.

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PROPOSAL 3: THE ADJOURNMENT PROPOSAL

        IXYS stockholders are being asked to approve the adjournment of the special meeting, if necessary, to solicit additional proxies if there are not sufficient votes to approve the merger proposal at the time of the special meeting.

        If this proposal is approved, under the merger agreement the special meeting may be adjourned (i) to any date that is within 20 business days of the date on which the IXYS special meeting was originally scheduled (or any later date to which such date may be extended pursuant to the provisions in the merger agreement described under "The Merger Agreement—Termination of the Merger Agreement" beginning on page 109) or (ii) with the prior written consent of Littelfuse, to any other date.

        If the special meeting is so adjourned, IXYS stockholders who have already submitted their proxies will be able to revoke them at any time prior to their use. If you sign and return a proxy and do not indicate how you wish to vote on any proposal, or if you indicate that you wish to vote in favor of the merger proposal but do not indicate a choice on the adjournment proposal, your shares of IXYS common stock will be voted in favor of the adjournment proposal. If you indicate, however, that you wish to vote against the merger proposal, your shares of IXYS common stock will only be voted in favor of the adjournment proposal if you indicate that you wish to vote in favor of that proposal.

        The affirmative vote of holders of a majority of the shares of IXYS common stock present in person or represented by proxy and entitled to vote on the adjournment proposal at the special meeting is required to approve the adjournment proposal.

        THE IXYS BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT IXYS STOCKHOLDERS VOTE "FOR" THE ADJOURNMENT PROPOSAL.

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THE MERGER

        This section of the proxy statement/prospectus describes the material aspects of the proposed merger. This section may not contain all of the information that is important to you. You should carefully read this entire proxy statement/prospectus and the documents incorporated by reference into this proxy statement/prospectus, including the full text of the merger agreement, a copy of which is attached to this proxy statement/prospectus as Annex A, for a more complete understanding of the proposed merger. In addition, important business and financial information about each of Littelfuse and IXYS is included in or incorporated by reference into this proxy statement/prospectus. See the section titled "Where You Can Find More Information" beginning on page 150.

Merger Consideration

        The merger agreement provides that, subject to the terms and conditions of the merger agreement, Merger Sub will be merged with and into IXYS, with IXYS surviving the initial merger as a wholly owned subsidiary of Littelfuse. Further to the terms of the merger agreement, IXYS, as the surviving corporation of the initial merger, will merge with and into Littelfuse (or a subsidiary of Littelfuse), with Littelfuse (or such subsidiary) continuing as the surviving corporation in the follow-on merger. Littelfuse intends to structure the follow-on merger as a merger of IXYS with and into a subsidiary of Littelfuse. Upon completion of the merger, each issued and outstanding share of IXYS common stock (other than (i) cancelled shares or (ii) dissenting shares) will be converted into the right to receive, at the election of the holder of such share and subject to proration, $23.00 in cash, less any applicable withholding taxes and without interest, or 0.1265 of a share of Littelfuse common stock. No fractional shares of Littelfuse common stock will be issued in the merger, and holders of IXYS common stock will instead receive cash in lieu of fractional shares of Littelfuse common stock.

        The merger consideration is subject to proration so that 50% of IXYS common stock issued and outstanding immediately prior to the effective time of the initial merger will be converted into cash consideration and the remaining IXYS common stock will be converted into stock consideration, based on an exchange ratio of 0.1265 of a share of Littelfuse common stock. Holders of IXYS common stock who do not make an election will be treated as having elected to receive cash consideration or stock consideration in accordance with the proration methodology in the merger agreement.

        Based on the number of shares of IXYS common stock outstanding as of October 16, 2017, Littelfuse would issue approximately 2.1 million shares of Littelfuse common stock to IXYS stockholders pursuant to the merger. The actual number of shares of Littelfuse common stock to be issued pursuant to the merger will be determined at completion of the merger based on the exchange ratio and the number of shares of IXYS common stock outstanding at such time. Based on the number of shares of IXYS common stock outstanding as of October 16, 2017, and the number of shares of Littelfuse common stock outstanding as of October 16, 2017, immediately after completion of the merger, former IXYS stockholders would own approximately 8% of the outstanding shares of Littelfuse common stock.

        Based on the closing stock price of Littelfuse common stock on [    ·    ], 2017, the most recent practicable date prior to the date of this proxy statement/prospectus, the per share value of IXYS common stock implied by the stock consideration is $[    ·    ]. The implied value of the stock consideration will fluctuate, however, as the market price of Littelfuse common stock fluctuates because the stock consideration is payable in a fixed number of shares of Littelfuse common stock. As a result, the value of the stock consideration that IXYS stockholders will receive upon completion of the merger could be greater than, less than or the same as the value of the stock consideration on the date of this proxy statement/prospectus or at the time of the IXYS special meeting. Accordingly, IXYS and Littelfuse encourage you to obtain current stock price quotations for Littelfuse common stock and IXYS common stock before deciding how to vote with respect to approval of the merger proposal.

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Background of the Merger

        IXYS management and the IXYS board of directors have periodically evaluated IXYS' competitive position and various strategic alternatives to enhance value for IXYS stockholders, including opportunities for acquisitions as well as a sale of IXYS either initiated by IXYS or in response to inquiries received from third parties expressing interest in a potential strategic combination, including from Littelfuse and Company A, a United States based publicly traded semiconductor company. The inquiries received from third parties prior to February, 2017 were of a preliminary nature and did not lead to a bona fide proposal with a purchase price or that was otherwise sufficiently compelling for the IXYS board of directors.

        On February 21, 2017, Eyal Altman, Vice President and General Manager—Automotive Electronics Business at Littelfuse, contacted Uzi Sasson, President and Chief Executive Officer of IXYS, by email to express interest in exploring a strategic combination between Littelfuse and IXYS. On March 11, 2017, Mr. Altman contacted Mr. Sasson by telephone to propose a meeting on March 20, 2017.

        On March 14, 2017, Littelfuse delivered a draft confidentiality agreement to IXYS. Following further communications, the parties entered into a confidentiality agreement on March 17, 2017.

        On March 20, 2017, Mr. Altman, David Heinzmann, President and Chief Executive Officer of Littelfuse, and Gordon Hunter, Executive Chairman of the Littelfuse board of directors, met with Messrs. Sasson and Zommer to discuss the respective businesses of Littelfuse and IXYS and a potential combination between Littelfuse and IXYS. Following further communications, the parties amended and restated the confidentiality agreement on April 10, 2017 to include a standstill provision.

        On May 5, 2017, Dave Coughlan, Vice President of Business Development at Littelfuse, contacted Mr. Sasson by telephone to inform him that Littelfuse was considering a proposal to acquire all outstanding shares of IXYS for a price of $21.35 per share. Mr. Sasson informed Mr. Coughlan that IXYS was willing to consider a proposal from Littelfuse. The closing trading price of IXYS common stock on May 5, 2017 was $13.90.

        On May 12, 2017, Mr. Coughlan contacted Mr. Sasson by telephone to inform him that Littelfuse was considering a revised proposal to acquire all outstanding shares of IXYS for a price of $21.75 per share. Mr. Sasson reiterated that IXYS was willing to consider a proposal from Littelfuse. The closing trading price of IXYS common stock on May 12, 2017 was $14.85.

        On May 15, 2017, Mr. Sasson contacted Mr. Coughlan by telephone to discuss the potential proposal shared by Littelfuse on May 12, 2017. Mr. Coughlan reiterated Littelfuse's interest in acquiring IXYS on the terms communicated on May 12, 2017.

        On May 31, 2017, Mr. Zommer met Mr. Heinzmann and Ian Highley, Senior Vice President and General Manager of the Semiconductor Business and Chief Technology Officer at Littelfuse, in Germany, where they discussed the respective businesses and operations of IXYS and Littelfuse. The next day Messrs. Heinzmann and Highley toured certain IXYS facilities.

        On June 5, 2017, Mr. Sasson contacted representatives of Needham & Company by telephone to discuss the possibility of exploring whether there was interest from third parties in an acquisition of IXYS. Mr. Sasson requested a proposal from Needham & Company to provide financial advisory services.

        On June 15, 2017, the IXYS board of directors met at the IXYS office in Milpitas, California, with James Jones, General Counsel of IXYS, and other members of IXYS management in attendance to discuss the indication by Littelfuse of a proposal for the acquisition of IXYS. At the request of the IXYS board of directors, representatives of Needham & Company joined the meeting to review and discuss with the IXYS board of directors potential strategic alternatives available to IXYS and

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Needham & Company's perspectives regarding consolidation in IXYS' industry and third parties that may have an interest in a transaction with IXYS. The IXYS board of directors authorized management to engage Needham & Company to assist the IXYS board of directors in any evaluation of a proposal from Littelfuse from a financial point of view and exploration of available strategic alternatives on the basis of Needham & Company's familiarity with IXYS, expertise in mergers and acquisitions and experience in the semiconductor industry.

        On June 16, 2017, the Chief Executive Officer and Chief Financial Officer of Company A met with Mr. Zommer and Mr. Sasson at the IXYS office in Milpitas, California and indicated that Company A was considering a proposal for the acquisition of all of the outstanding shares of IXYS. Messrs. Zommer and Sasson informed Company A that IXYS was willing to consider a proposal from Company A.

        On June 23, 2017, IXYS entered into an engagement letter with Needham & Company for the provision of financial advisory services in connection with a potential sale of IXYS.

        On June 23, 2017, Mr. Jones contacted Ryan Stafford, Executive Vice President, Chief Legal and Human Resources Officer and Corporate Secretary of Littelfuse, by telephone to discuss a proposed meeting of the IXYS board of directors and members of Littelfuse senior management on June 27, 2017 and June 28, 2017 to further discuss the potential proposal outlined by Littelfuse on May 5, 2017.

        On June 27, 2017, Messrs. Zommer and Sasson met in person with Messrs. Heinzmann and Hunter to discuss IXYS and its business as well as Littelfuse and its business and how the IXYS business may fit within a combined organization.

        On June 28, 2017, the IXYS board of directors met at a hotel in Milpitas, California, with Mr. Jones and representatives of Littelfuse, Morgan Stanley & Co. LLC (referred to in this proxy statement/prospectus as Morgan Stanley), financial advisor to Littelfuse, and Needham & Company also in attendance. Messrs. Heinzmann, Hunter and Coughlan delivered a presentation on Littelfuse and its business and how the IXYS business may fit within a combined organization. Mr. Heinzmann presented a non-binding proposal for an acquisition of all of the outstanding shares of IXYS for a price of $22.35 per share, including a mix of stock and cash consideration. The Littelfuse proposal was subject to satisfactory completion of due diligence and contingent on the parties entering into an exclusivity agreement. The proposal was not subject to a financing condition. The closing trading price of IXYS common stock on June 28, 2017 was $16.80. Following the conclusion of the Littelfuse presentation and the departure of representatives of Littelfuse, the IXYS board of directors discussed the Littelfuse proposal, the Company A indication of interest and other strategic alternatives with representatives of Needham & Company. At the request of the IXYS board of directors, the Needham & Company representatives provided the IXYS board of directors with an update regarding market trends in the semiconductor industry. The Needham & Company representatives then discussed with the IXYS board of directors and management potential parties to be contacted in connection with a strategic transaction. The IXYS board of directors instructed IXYS management and Needham & Company to continue non-exclusive discussions with Littelfuse and to conduct outreach to other potential acquirers, including to enter into confidentiality agreements with other potential acquirers.

        On June 28, 2017, Messrs. Sasson, Zommer and Jones met with representatives of Needham & Company at the IXYS office in Milpitas, California and authorized Needham & Company to contact third parties and determine if there was interest from third parties for a potential acquisition of IXYS. After that meeting, representatives of Needham & Company began to contact third parties pursuant to that authorization.

        On June 29, 2017, Messrs. Zommer and Sasson met at the IXYS office in Milpitas, California with the Chief Executive Officer and two senior management representatives of Company A to discuss

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IXYS and its business, Company A and its business and how the IXYS business may fit within a combined organization.

        On July 5, 2017, a representative of Company B, a United States based publicly traded semiconductor company, contacted Needham & Company to indicate that it was considering a proposal for a strategic transaction with IXYS. Based on the instruction of the IXYS board of directors, representatives of Needham & Company delivered a draft confidentiality agreement to Company B on July 5, 2017. Following further communications, IXYS and Company B entered into a confidentiality agreement on July 13, 2017, which included a standstill provision.

        On July 7, 2017, Company A contacted Mr. Sasson by telephone to communicate that it was considering a proposal for the acquisition of all of the outstanding shares of IXYS for a price in a preliminary range of $23.00-25.00 per share, subject to conducting due diligence, and indicated flexibility in using stock or cash consideration for the acquisition.

        On July 7, 2017, Mr. Coughlan contacted Mr. Sasson by telephone to discuss the status of the potential transaction. Mr. Sasson communicated to Mr. Coughlan that a purchase price of $22.35 per share was not likely to be supported by the IXYS board of directors and informed him that IXYS had been approached by another party which had indicated a purchase price of around $25.00 per share.

        On July 7, 2017, based on the instruction of the IXYS board of directors, representatives of Needham & Company delivered a draft confidentiality agreement to Company A. Following further communications, IXYS and Company A entered into a confidentiality agreement on July 19, 2017, which included a standstill provision.

        On July 19, 2017, the IXYS board of directors met telephonically, with Mr. Jones and representatives of Needham & Company and Latham & Watkins LLP, counsel to IXYS, also in attendance. At the request of the IXYS board of directors, representatives of Needham & Company presented an update regarding discussions with potential acquirers, including Company A's indication on July 7, 2017 that it was considering a proposal. A representative of Needham & Company presented preliminary financial analyses with respect to IXYS and potential strategic combinations. The IXYS board of directors instructed representatives of Needham & Company to continue its outreach to potential acquirers, including enabling access to due diligence materials, and to seek final written proposals from any interested acquirers, including Littelfuse and Company A, by July 26, 2017. A representative from Latham & Watkins reviewed with the members of the IXYS board of directors their fiduciary duties to IXYS and its stockholders under Delaware law in connection with a sale of IXYS.

        On July 20, 2017, based on the instruction of the IXYS board of directors, Needham & Company provided Littelfuse, Company A and Company B with access to a virtual data room with respect to IXYS and its business.

        On July 24, 2017, representatives of each of Littelfuse and Company A separately met by telephone with IXYS management and representatives of Needham & Company for due diligence discussions.

        On July 25, 2017, Littelfuse submitted to Needham & Company a written non-binding proposal for the acquisition of all of the outstanding shares of IXYS for a price of $23.00 per share, including a mix of stock and cash consideration that provided for 45% of IXYS shares to be converted into the stock consideration. Littelfuse communicated to Needham & Company that the proposal was contingent on the parties entering into an exclusivity agreement. The closing trading price of IXYS common stock on July 25, 2017 was $17.40.

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        On July 26, 2017, a representative of Company B communicated to a representative of Needham & Company that Company B would not submit a proposal for the acquisition of IXYS because management of Company B did not believe there was a good strategic fit with IXYS.

        On July 26, 2017, Company A submitted to Needham & Company a written non-binding proposal for the acquisition of all of the outstanding shares of IXYS for a price in the range of $20.00-21.00 per share, including a mix of stock and cash consideration. The proposal was contingent on the parties entering into an exclusivity agreement. The closing trading price of IXYS common stock on July 26, 2017 was $17.55. A representative of Needham & Company asked a representative of Company A whether Company A would consider increasing its proposed purchase price, and the representative of Company A indicated that it was unlikely Company A would increase its proposed purchase price.

        On July 26, 2017, the IXYS board of directors met telephonically, with Mr. Jones and representatives of Needham & Company and Latham & Watkins also in attendance. A representative from Latham & Watkins reviewed with the members of the IXYS board of directors their fiduciary duties to IXYS and its stockholders under Delaware law in connection with a sale of IXYS. Representatives of Needham & Company presented an update regarding discussions with potential acquirers, including the revised proposal received from Littelfuse on July 25, 2017 and the initial proposal received from Company A on July 26, 2017, and updated preliminary financial analyses with respect to IXYS and potential strategic combinations. The IXYS board of directors discussed the relative merits of each of the Littelfuse and Company A proposals and considered further negotiation of the purchase price or entering into an exclusivity arrangement with either party. The IXYS board of directors evaluated various factors, including the higher proposed purchase price from Littelfuse, communication by Littelfuse that its proposal submitted on July 25, 2017 was its final proposal, communication by Company A that it was unlikely to improve its proposal submitted on July 26, 2017, the extended period of time during which IXYS and Needham & Company had engaged with each of Littelfuse and Company A and their familiarity with each company, the uncertainty of potential interest from any other party based on the outreach to potential acquirers conducted by Needham & Company and the possibility of Littelfuse withdrawing its proposal or otherwise indicating it was not prepared to proceed with a transaction if IXYS declined to enter into an exclusivity agreement or requested a further increase in the purchase price. Following the discussion, the IXYS board of directors authorized IXYS management to enter into a 21-day exclusivity agreement with Littelfuse and to commence negotiations with Littelfuse on the basis of a proposed purchase price of $23.00 per share, including a mix of cash and stock consideration. Following the IXYS board meeting, representatives of Needham & Company contacted a representative of Company A and indicated that IXYS was going to proceed with another company, and there was no further response from Company A. On July 29, 2017, IXYS entered into the exclusivity agreement with Littelfuse.

        From June 28, 2017, when the IXYS board of directors authorized IXYS management and Needham & Company to conduct outreach to potential acquirers, through July 29, 2017, when IXYS entered into the exclusivity agreement with Littelfuse, IXYS management and representatives of Needham & Company reached out to or were contacted by 13 parties regarding their possible interest in an acquisition of IXYS. During this period, IXYS entered into confidentiality agreements with three parties, namely Littelfuse, Company A and Company B, all of which contained standstill provisions which terminated in accordance with their terms upon IXYS' entry into the merger agreement. Additionally, IXYS management had meetings with and received written proposals from two parties, Littelfuse and Company A.

        On August 4, 2017 and on August 9, 2017, representatives of Littelfuse and Morgan Stanley met with IXYS management and representatives of Needham & Company to discuss the due diligence being performed by Littelfuse and IXYS.

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        On August 8, 2017, Latham & Watkins received an initial draft of the merger agreement from Wachtell, Lipton, Rosen & Katz, counsel to Littelfuse. Throughout the period that IXYS and Littelfuse were negotiating the merger agreement, Messrs. Sasson and Jones spoke on numerous occasions with Latham & Watkins and provided updates to the IXYS board of directors on the status of negotiations. Furthermore, Mr. Sasson communicated on several occasions with Mr. Coughlan to discuss the terms of the merger agreement.

        On August 14, 2017, Latham & Watkins sent its comments to the draft of the merger agreement to Wachtell, Lipton, Rosen & Katz.

        On August 16, 2017, the IXYS board of directors met telephonically, with Mr. Jones and representatives of Needham & Company and Latham & Watkins also in attendance. Representatives of Latham & Watkins provided an update on the potential transaction with Littelfuse, including a summary of the material terms of the merger agreement submitted by Littelfuse. Representatives of Needham & Company presented Needham & Company's preliminary financial analyses of the consideration that would be payable to IXYS' stockholders pursuant to the proposed transaction with Littelfuse.

        On August 18, 2017, Latham & Watkins received a revised draft of the merger agreement from Wachtell, Lipton, Rosen & Katz. Following the receipt of the draft on August 18, 2017 and through August 25, 2017, Latham & Watkins and Wachtell, Lipton, Rosen & Katz continued to negotiate the terms of the merger agreement.

        On August 22, 2017, the IXYS board of directors met telephonically, with Mr. Jones and representatives of Latham & Watkins also in attendance. Messrs. Sasson and Jones provided an update on the discussion of the definitive documentation with Littelfuse, including substantive issues which continued to be negotiated to achieve improved terms for IXYS stockholders, including among others, the proportion of outstanding IXYS shares that would be converted into the stock consideration and the cash and stock election mechanics.

        On August 23, 2017, the IXYS board of directors met telephonically, with Mr. Jones and representatives of Latham & Watkins also in attendance. Mr. Sasson provided an update on the discussion of definitive documentation with Littelfuse, including substantive issues which continued to be negotiated to achieve improved terms for IXYS stockholders, including among others, the termination fee payable by IXYS under certain circumstances and the timing for the closing of a transaction. At IXYS' request, Littelfuse agreed to increase the proportion of outstanding IXYS shares that would be converted into the stock consideration from 45% to 50%.

        On August 25, 2017, the IXYS board of directors met telephonically, with Mr. Jones and representatives of Latham & Watkins and Needham & Company also in attendance. Representatives of Latham & Watkins reviewed with the members of the IXYS board of directors their fiduciary duties to IXYS and its stockholders under Delaware law in connection with a sale of IXYS. Representatives of Latham & Watkins then provided an update on the transaction with Littelfuse, including the terms of the final merger agreement negotiated with Littelfuse. Representatives of Needham & Company presented Needham & Company's financial analyses of the consideration pursuant to the proposed transaction with Littelfuse and delivered Needham & Company's oral opinion to the IXYS board of directors, which was subsequently confirmed by delivery of a written opinion dated August 25, 2017, that, as of that date, and based upon and subject to the assumptions, qualifications, limitations and other matters set forth in its written opinion, the consideration of $23.00 in cash or 0.1265 of a share of Littelfuse common stock per share of IXYS common stock to be received by the holders of IXYS common stock (other than the holders of cancelled shares and dissenting shares) pursuant to the merger agreement was fair, from a financial point of view, to such holders. Following further discussion, and taking into account the factors described below in greater detail under the section entitled "The Merger—IXYS' Reasons for the Merger; Recommendation of the IXYS Board of Directors"

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beginning on page 55, the IXYS board of directors unanimously determined that the terms of the merger agreement and the merger are fair to, and in the best interests of, IXYS and its stockholders, and declared it advisable, for IXYS to enter into the merger agreement. A representative of Latham & Watkins then reviewed the anticipated timing for the execution of the merger agreement, the announcement of the transaction and initial filings with the SEC.

        Following the August 25, 2017 meeting of the IXYS board of directors, IXYS and Littelfuse executed the merger agreement and on August 28, 2017 announced the transaction in a press release prior to the opening of US stock markets.

IXYS' Reasons for the Merger; Recommendation of IXYS Board of Directors

        At its August 25, 2017 meeting held to evaluate the proposed merger, the IXYS board of directors unanimously approved the merger agreement and determined that the terms of the merger are fair to and in the best interests of IXYS stockholders. The IXYS board of directors recommends that IXYS stockholders vote:

            1.     "FOR" the merger proposal;

            2.     "FOR" the merger-related compensation proposal; and

            3.     "FOR" the adjournment proposal.

        In evaluating the merger and the merger agreement and arriving at its determination, the IXYS board of directors consulted with IXYS' senior management, IXYS' financial advisor, Needham & Company, and IXYS' outside legal counsel, Latham & Watkins LLP, and considered a number of substantive factors, both positive and negative, and potential benefits and detriments of the merger to IXYS and its stockholders. The IXYS board of directors believed that, taken as a whole, the following factors supported its decision to approve the proposed merger:

    Merger Consideration. The value of the merger consideration to be received by IXYS stockholders in relation to (1) the market prices of IXYS common stock prior to the IXYS board of directors' approval of the merger agreement; and (2) the value that could potentially be obtained through other strategic alternatives available to IXYS.

    Premium to Trading Price of IXYS Common Stock. The fact that the cash consideration of $23.00 per share and the implied value of the stock consideration of $22.55 per share, based on the $178.26 closing price per share of Littelfuse common stock on August 25, 2017, the last full trading day before the announcement of the merger, were both higher than the closing price per share of IXYS' common stock at any date in the past five years and represented a significant premium over the market prices at which IXYS common stock had previously traded, including a premium on the value of the cash consideration of approximately:

    44% over the closing price per share of IXYS common stock on August 25, 2017;

    39% over the 30-day average closing price per share of IXYS common stock as of August 25, 2017; and

    40% over the 60-day average closing price per share of IXYS common stock as of August 25, 2017.

    Uncertainty of Future Common Stock Market Price. The IXYS board of directors considered IXYS' business, assets, financial condition, results of operations, management, competitive position and prospects, as well as current industry, economic and stock and credit market conditions. The IXYS board of directors also considered IXYS' financial plan and the initiatives and the potential execution risks associated with such plan. In connection with these considerations, the IXYS board of directors considered the attendant risk that if IXYS remained

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      independent IXYS common stock may not trade at levels equal to or greater than the value of the merger consideration in the near term, over an extended period of time or at all.

    Negotiations with Littelfuse. The benefits that IXYS and its advisors were able to obtain during its negotiations with Littelfuse, including an increase in Littelfuse's offer price per share from the beginning of the process to the end of the negotiations. The IXYS board of directors believed that the consideration reflected in the merger agreement was the best transaction that could be obtained by IXYS stockholders from Littelfuse at the time, and that there was no assurance that a more favorable opportunity to sell IXYS would arise later or through any alternative transaction.

    Stockholder Election Opportunity. The fact that IXYS stockholders would have the right to elect to receive the merger consideration either in cash or shares of Littelfuse common stock, subject to proration.

    Significant Portion of Merger Consideration in Cash. The fact that 50% of the merger consideration will be paid in cash, giving IXYS stockholders the opportunity to immediately realize value for a significant portion of their investment and providing certainty of value. The IXYS board of directors also considered the fact that IXYS stockholders would be able to reinvest the cash consideration received in the merger in shares of Littelfuse common stock if they desired to do so.

    Participation in Potential Upside. The benefits of the combined company that could result from the merger, including the potential to realize synergies. The fact that, since a portion of the merger consideration will be paid in Littelfuse common stock, IXYS stockholders will benefit from an approximately 8% pro forma continuing equity ownership in Littelfuse (based on share data of IXYS and Littelfuse on August 25, 2017) and have the opportunity to participate in any future earnings or growth of the combined company and future appreciation in the value of Littelfuse common stock following the merger should they determine to retain the Littelfuse common stock payable in the merger.

    Fixed Exchange Ratio for Stock Portion of Merger Consideration. The fact that because the stock consideration is based on a fixed exchange ratio of 0.1265 of a share of Littelfuse common stock, IXYS stockholders receiving the stock consideration will have the opportunity to benefit from any increase in the trading price of shares of Littelfuse common stock between the announcement of the merger agreement and the completion of the merger and that the cash portion of the merger consideration will limit the impact of a decline in the trading price of Littelfuse common stock on the aggregate value of the merger consideration.

    Tax Treatment. The fact that the merger is intended to qualify as a "reorganization" within the meaning of Section 368(a) of the Code and, assuming the merger so qualifies, a holder who exchanges shares of IXYS common stock solely for stock consideration generally will not recognize any gain or loss for U.S. federal income tax purposes, other than in respect of cash in lieu of a fractional share of Littelfuse common stock.

    Expected Cost Synergies. The expectation that the combined company will recognize anticipated annualized cost synergies following consummation of the proposed transaction, which IXYS stockholders will benefit from as continuing stockholders of Littelfuse. The IXYS board of directors also considered that there could be no assurance that any particular amount of such synergies would be achieved following completion of the merger or the timeframe in which they would be achieved.

    Financial Advisor's Financial Analyses and Opinion. The oral opinion rendered by representatives of Needham & Company to the IXYS board of directors on August 25, 2017, which was subsequently confirmed in writing, that as of such date, and based upon and subject

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      to the assumptions, qualifications, limitations and other matters set forth in its written opinion, as described under "—Opinion of IXYS' Financial Advisor" beginning on page 64 of this proxy statement/prospectus, the merger consideration to be received by the holders of shares of IXYS common stock (other than the holders of cancelled shares and dissenting shares) pursuant to the merger agreement was fair, from a financial point of view, to such holders.

    Likelihood of Consummation. The likelihood that the merger would be completed, in light of, among other things, the conditions to the merger, the absence of a financing condition, the efforts required to obtain regulatory approvals, and the provisions of the merger agreement in the event of various breaches by Littelfuse.

    Board Representation. That Dr. Zommer will join the Littelfuse board of directors.

    Terms of the Merger Agreement. The terms and conditions of the merger agreement, including:

    the representations, warranties and covenants of the parties, the conditions to the parties' obligations to complete the merger and their ability to terminate the merger agreement;

    the provisions of the merger agreement that allow IXYS to engage in negotiations with, and provide information to, a third party that makes an unsolicited written bona fide proposal relating to an alternative transaction, if the IXYS board of directors has determined in good faith, after consultation with its outside legal counsel and financial advisors, that such proposal constitutes or could reasonably be expected to result in a transaction that is superior to the proposed transaction with Littelfuse and IXYS complies with certain procedural requirements;

    the provisions of the merger agreement that allow the IXYS board of directors to change its recommendation in favor of the adoption of the merger agreement in response to a company superior proposal and/or terminate the merger agreement in order to accept a company superior proposal if the IXYS board of directors has determined in good faith, after consultation with its outside legal counsel and financial advisors, that a proposal relating to an alternative transaction constitutes a company superior proposal (including taking into account any modifications to the terms of the merger agreement that are proposed by Littelfuse and, in connection with the termination of the merger agreement, payment to Littelfuse of a $28.5 million termination fee), subject to IXYS' compliance with certain procedural requirements;

    the provisions of the merger agreement that allow the IXYS board of directors to change its recommendation in favor of the adoption of the merger agreement (other than in response to the receipt of a written unsolicited bona fide proposal relating to an alternative transaction, which is subject to the preceding sub-bullet above) if the IXYS board of directors has determined in good faith, after consultation with its outside legal counsel, that failure to take such action would be inconsistent with its directors' fiduciary duties (including taking into account any modifications to the terms of the merger agreement that are proposed by Littelfuse), subject to IXYS' compliance with certain procedural requirements;

    the belief of the IXYS board of directors that the termination fee provisions were not likely to unduly discourage competing third-party proposals or reduce the price of such proposals, that such provisions are customary for transactions of this size and type, and that the $28.5 million termination fee, representing approximately 3.8% of the equity value implied by the proposed transaction, was reasonable in the context of comparable transactions; and

    the ability of IXYS to specifically enforce the terms of the merger agreement.

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    Strategic Alternatives. The IXYS board of directors, with the assistance of representatives of Needham & Company, considered the strategic and business considerations relating to a potential transaction with Littelfuse and the risks and benefits of a potential transaction compared to other potential strategic alternatives and concluded that while each of such other potential alternatives had a variety of qualitative factors that could make it attractive or cause concerns, a potential transaction with Littelfuse would likely deliver value to IXYS stockholders that was higher than the values that could be achieved for IXYS stockholders in other potential strategic alternatives.

    Absence of Competing Offers.  The IXYS board of directors noted that, other than the Company A Proposal, IXYS had not received any bona fide written proposals concerning alternative transactions. The IXYS board of directors also believed that the benefits of soliciting interest from other potential parties were outweighed by a number of risks, including that such solicitation would further increase market speculation and jeopardize or, at a minimum, delay the proposed transaction with Littelfuse. The IXYS board of directors also observed that, in the event that any third party were to seek to make such proposal, IXYS retained the ability to consider unsolicited proposals after the execution of the merger agreement until the meeting of the IXYS stockholders to vote on the merger proposal and to enter into an agreement with respect to an alternative acquisition proposal under certain circumstances (concurrently with terminating the merger agreement and paying a $28.5 million termination fee to Littelfuse).

    Littelfuse's Business and Reputation.  The results of the due diligence investigation that IXYS' senior management conducted with the assistance of its advisors on Littelfuse with respect to certain matters and Littelfuse's business reputation and capabilities of Littelfuse and its management.

    Financing Strength of Littelfuse.  The likelihood that Littelfuse would be able to finance the merger given Littelfuse's financial resources and financial profile.

    Availability of Appraisal Rights.  The fact that appraisal rights would be available to holders of IXYS common stock under Delaware law and that there was no condition in the merger agreement relating to the maximum number of shares of IXYS common stock that could dissent from the merger.

    Stockholders' Ability to Reject the Merger.  The IXYS board of directors considered the fact that the merger is subject to approval by IXYS stockholders.

        The IXYS board of directors also considered certain potentially negative factors in its deliberations concerning the merger, including the following:

    Fixed Stock Ratio of Merger Consideration.  The fact that because the stock portion of the merger consideration is a fixed exchange ratio of shares of Littelfuse common stock to IXYS common stock, IXYS stockholders could be adversely affected by a decrease in the trading price of Littelfuse common stock during the pendency of the merger, and the fact that the merger agreement does not provide IXYS with a termination right or other similar protection relating to the trading price of Littelfuse common stock. The IXYS board of directors determined that this structure was appropriate and the risk acceptable in view of factors such as:

    the IXYS board of directors' review of the relative intrinsic values and financial performance of Littelfuse and IXYS; and

    the fact that IXYS stockholders may elect cash consideration, subject to proration, which limits the impact of a decline in the trading price of Littelfuse common stock on the value of the merger consideration.

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    Possible Failure to Achieve Synergies.  The risk that the potential benefits and synergies sought in the merger will not be realized or will not be realized within the expected time period, and the risk associated with the integration by Littelfuse of IXYS.

    Smaller Ongoing Equity Participation in the Combined Company by IXYS Stockholders.  The fact that because only 50% of the merger consideration will be in the form of Littelfuse common stock, IXYS stockholders will have a smaller ongoing equity participation in the combined company (and, as a result, a smaller opportunity to participate in any future earnings or growth of the combined company and future appreciation in the value of Littelfuse common stock following the merger) than they have in IXYS.

    Risk of Non-Completion.  The possibility that the merger might not be completed, including as a result of the failure to obtain regulatory approvals or the failure of IXYS stockholders to approve the merger proposal, and the effect the resulting public announcement of the termination of the merger agreement may have on:

    the trading price of IXYS common stock; and

    IXYS' business and operating results, particularly in light of the costs incurred in connection with the transaction.

    Possible Deterrence of Competing Offers.  The risk that various provisions of the merger agreement, including the requirement that IXYS must pay to Littelfuse a termination fee of $28.5 million if the merger agreement is terminated under certain circumstances, may discourage other parties potentially interested in an acquisition of, or combination with, IXYS from pursuing that opportunity.

    Possible Disruption of the Business and Costs and Expenses.  The possible disruption to IXYS' business that may result from the merger, the resulting distraction of IXYS' management and potential attrition of IXYS' employees, as well as the costs and expenses associated with completing the merger.

    Restrictions on Operation of IXYS' Business.  The requirement that IXYS conduct its business in all material respects in the ordinary course prior to completion of the merger and subject to specified restrictions unless Littelfuse provides its prior written consent (which consent may not be unreasonably withheld, delayed or conditioned), which might delay or prevent IXYS from undertaking certain business opportunities that might arise pending completion of the merger.

    Other Risks.  The risks described under "Risk Factors" beginning on page 31 of this proxy statement/prospectus.

        The IXYS board of directors concluded that the potentially negative factors associated with the proposed merger were significantly outweighed by the potential benefits that it expected the IXYS stockholders would achieve as a result of the merger, including the belief of the IXYS board of directors that the proposed merger would maximize the immediate value of IXYS stockholders' shares and minimize the risks and uncertainty affecting the future prospects of IXYS, including the potential execution risks associated with its stand-alone financial plan. Accordingly, the IXYS board of directors determined that the merger agreement and the merger are fair to, and in the best interests of, IXYS and IXYS stockholders.

        In addition, the IXYS board of directors was aware of and considered the interests that IXYS' directors and executive officers may have with respect to the merger that differ from, or are in addition to, the interests of stockholders of IXYS generally, as described under "—Interests of IXYS' Directors and Executive Officers in the Merger" beginning on page 74 of this proxy statement/prospectus.

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        The foregoing discussion of the information and factors considered by the IXYS board of directors is not exhaustive, but IXYS believes it includes all the material factors considered by the IXYS board of directors. In view of the wide variety of factors considered in connection with its evaluation of the merger and the complexity of these matters, the IXYS board of directors did not consider it practicable to, and did not attempt to, quantify or otherwise assign relative or specific weight or values to any of these factors. Rather, the IXYS board of directors viewed its position and recommendation as being based on an overall analysis and on the totality of the information presented to and factors considered by it. In addition, in considering the factors described above, individual directors may have given different weights to different factors. After considering this information, the IXYS board of directors approved the merger agreement and the merger and recommended that IXYS stockholders adopt the merger agreement.

        This explanation of IXYS' reasons for the merger and other information presented in this section is forward-looking in nature and, therefore, should be read in light of the factors described under "Cautionary Statements Regarding Forward-Looking Statements" beginning on page 29 of this proxy statement/prospectus.

Certain Financial Projections Utilized by the IXYS Board of Directors and IXYS' Financial Advisor

        In the ordinary course, each year IXYS management prepares certain unaudited prospective financial information for the subsequent fiscal year for internal budgeting and business planning purposes. The annual budget forecast for fiscal year 2018 was prepared by management in May 2017 (referred to in this proxy statement/prospectus as the 2018 budget forecast).

        Although IXYS has publicly issued limited quarterly guidance concerning IXYS management's expectations regarding financial performance for the subsequent fiscal quarter, it does not, as a matter of course, make public disclosure of detailed forecasts or projections of its expected financial performance for extended periods due to, among other things, the inherent difficulty of accurately predicting future periods; and the likelihood that the underlying assumptions and estimates may prove incorrect.

        For internal purposes and in connection with the process leading to the merger agreement, IXYS management prepared certain unaudited prospective financial information for the fiscal years 2018 through 2020 (referred to in this proxy statement / prospectus as the initial management forecast). The initial management forecast differed from the annual budget forecast in that it reflected the information then available to IXYS management and included prospective financial information for fiscal years 2019 and 2020 based on management estimates for growth rates for revenues and expenses. The initial management forecast was provided to Needham & Company on July 21, 2017 and made available to Littelfuse, Company A and Company B with GAAP financial measures on July 21, 2017 and non-GAAP financial measures on July 25, 2017. The initial management forecast was included in the draft materials presented by Needham & Company to the IXYS board of directors on July 26, 2017.

        The unaudited prospective financial information in the initial management forecast was revised to reflect the actual financial results of IXYS for the first quarter of fiscal year 2018 ended June 30, 2017 (referred to in this proxy statement / prospectus as the final management forecast). The final management forecast was the only forecast discussed herein that was relied on by Needham & Company in connection with its opinion and related financial analyses that were presented to the IXYS board of directors on August 25, 2017. The presentation to the IXYS board of directors included unlevered free cash flows for IXYS for the projected six months ending March 31, 2018 and the projected fiscal years ending March 31, 2019 and 2020 derived by Needham & Company from the final management forecast for purposes of its discounted cash flow analysis as summarized below under "—Opinion of IXYS' Financial Advisor."

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        IXYS is including the final management forecast in this proxy statement / prospectus solely because it was the most recent financial information used by Needham & Company in connection with its financial analyses summarized below under "—Opinion of IXYS' Financial Advisor" and made available to the IXYS board of directors in connection with its evaluation of the merger and because, other than reflecting IXYS' actual financial results for the first quarter of fiscal 2018, the final management forecast reflected the same results as the initial management forecast made available to Littelfuse, Company A and Company B. The IXYS board of directors did not rely on any forecasts other than the final management forecast in reaching its determination on August 25, 2017 to approve the merger agreement and the transactions contemplated thereby and to recommend that IXYS' stockholders vote for the merger proposal.

        The final management forecast was based solely upon information available to IXYS management, and estimates and assumptions made by IXYS management, at the time when the final management forecast was prepared. As a result, the final management forecast does not necessarily reflect IXYS' current estimates and does not take into account any circumstances or events occurring after the date it was prepared, and some or all of the assumptions made regarding, among other things, the timing of certain occurrences or impacts, may have changed since such date. In addition, the final management forecast does not give effect to the merger or any changes to IXYS' operations or strategy that may be implemented as a result of the announcement of the merger or following the consummation of the merger or to any costs incurred in connection with the merger. Further, the final management forecast does not take into account the effect of any failure of the consummation of the merger to occur and should not be viewed as accurate or continuing in that context.

        The final management forecast was necessarily based on a variety of assumptions and estimates. Certain of these assumptions and estimates either have not or may not be realized. All such estimates and assumptions are inherently subject to significant business, economic and competitive uncertainties and contingencies, all of which are difficult to predict and many of which are beyond IXYS' control. In addition, the final management forecast covers multiple years, and such information by its nature becomes more uncertain with each successive year. Moreover, the final management forecast is based on certain future business decisions that are subject to change. The inclusion of the final management forecast in this proxy statement / prospectus should not be regarded as an indication that such unaudited prospective financial information will be predictive of actual future results, and the final management forecast should not be relied upon as such. The final management forecast is a forward-looking statement. Accordingly, there can be no assurance that any of the assumptions and estimates used to prepare the final management forecast will necessarily prove to be accurate, and actual results may differ materially from those shown in the final management forecast.

        The final management forecast is not being included in this proxy statement / prospectus in order to influence any IXYS stockholder's decision as to whether or not to approve the merger or whether or not to seek appraisal rights with respect to shares of IXYS common stock held by such stockholder. The inclusion of the final management forecast in this proxy statement / prospectus should not be regarded as an indication that IXYS or any of IXYS' respective advisors or representatives considered or consider the final management forecast to necessarily be an accurate prediction of future results or events, and the final management forecast should not be relied upon as such. None of IXYS or any of IXYS' advisors or representatives has made or makes any representation regarding the information contained in the final management forecast or assumes any responsibility for the validity, reasonableness, accuracy or completeness of the final management forecast included in this proxy statement / prospectus. In particular, IXYS has not made any representation to any other person concerning the accuracy of the final management forecast. The final management forecast should be read together with the historical financial statements of IXYS, which have been filed with the SEC, and the other information regarding IXYS contained elsewhere and incorporated by reference in this proxy statement / prospectus.

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        EXCEPT AS MAY BE REQUIRED BY APPLICABLE SECURITIES LAWS, NONE OF IXYS OR ANY OF IXYS' ADVISORS OR REPRESENTATIVES INTENDS TO, AND DISCLAIMS ANY OBLIGATION TO, UPDATE, CORRECT OR OTHERWISE REVISE OR RECONCILE THE FINAL MANAGEMENT FORECAST TO REFLECT CIRCUMSTANCES EXISTING OR EVENTS OCCURRING AFTER THE DATE WHEN SUCH FINAL MANAGEMENT FORECAST WERE PREPARED, EVEN IN THE EVENT THAT ANY OR ALL OF THE ASSUMPTIONS UNDERLYING SUCH FINAL MANAGEMENT FORECAST ARE NO LONGER APPROPRIATE. IXYS' STOCKHOLDERS ARE CAUTIONED NOT TO PLACE UNDUE RELIANCE ON THE FINAL MANAGEMENT FORECAST INCLUDED IN THIS PROXY STATEMENT / PROSPECTUS.

        The final management forecast was not prepared with a view toward public disclosure, nor was it prepared with a view toward compliance with published guidelines of the SEC or the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of prospective financial information. The final management forecast does not purport to present operations in accordance with U.S. GAAP, and IXYS' independent registered public accounting firm has not audited, reviewed, examined, compiled or otherwise applied or performed any procedures with respect to the final management forecast or any other forecast or any information contained therein, nor have they expressed any opinion or given any form of assurance with respect to such information or its reasonableness, achievability or accuracy, and accordingly such registered public accounting firm assumes no responsibility therefor. The final management forecast includes non-GAAP financial measures. Non-GAAP financial measures are not prepared in accordance with GAAP and should be considered as a supplement to, not a substitute for, or superior to, the corresponding measures calculated in accordance with GAAP.

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Final Management Forecast

        A summary of the final management forecast is set forth below. The income and expense information is provided on a non-GAAP basis, excluding stock-based compensation and amortization of acquired intangibles as expenses.

 
  Fiscal Year Ending March 31,  
US$ in Millions (except per share amounts)
  2018E   2019E   2020E  

Revenue

  $ 351.1   $ 371.9   $ 394.7  

Cost of Goods Sold (Non-GAAP)

    (231.5 )   (236.8 )   (244.1 )

Gross Profit (Non-GAAP)

    119.7     135.1     150.6  

Operating Expenses:

   
 
   
 
   
 
 

Research, Development, and Engineering

    (32.6 )   (36.8 )   (38.8 )

Selling, General, and Administrative

    (38.8 )   (41.8 )   (44.3 )

Total Operating Expenses (Non-GAAP)

    (71.5 )   (78.6 )   (83.1 )

Operating Income (Non-GAAP)

    48.2     56.4     67.5  

Other Income (Expense)

   
(0.2

)
 
0.4
   
0.4
 

Interest Income

    0.2     0.2     0.2  

Interest Expense

    (2.6 )   (2.6 )   (2.6 )

Total Other Income(Expense)

    (2.6 )   (1.9 )   (1.9 )

Earnings Before Income Tax Provisions

    45.6     54.5     65.6  

Provisions for Income Tax (Non-GAAP)

    (11.9 )   (14.6 )   (17.1 )

Net Income (Non-GAAP)

  $ 33.6   $ 40.0   $ 48.5  

Earnings per Share (Non-GAAP)

  $ 1.02   $ 1.17   $ 1.40  

Weighted Average Shares Used in per Share Calculation (Diluted)

    32.9     34.0     34.8  

Net Income (Non-GAAP)

 
$

33.6
 
$

40.0
 
$

48.5
 

Provisions for Income Tax (Non-GAAP)

    11.9     14.6     17.1  

Interest Expense

    2.6     2.6     2.6  

Depreciation

    7.4     8.0     8.9  

EBITDA

  $ 55.6   $ 65.1   $ 77.0  

 

 
   
  Fiscal Year
Ending March 31,
 
 
  Six Months
Ending
March 31, 2018
 
 
  2019E   2020E  

Net Income (Non-GAAP)

  $ 18.5   $ 40.0   $ 48.5  

Income Tax Expense (Non-GAAP)

    6.7     14.6     17.1  

Interest Expense

    1.3     2.6     2.6  

Depreciation

    3.8     8.0     8.9  

EBITDA

  $ 30.2   $ 65.1   $ 77.0  

EBIT

  $ 26.3   $ 56.4   $ 67.5  

Cash Taxes

    (6.2 )   (13.5 )   (15.9 )

Depreciation

   
3.8
   
8.0
   
8.9
 

Capital Expenditures

    (5.2 )   (8.0 )   (8.9 )

Increase in Working Capital

    (2.6 )   (6.0 )   (4.1 )

Unlevered Free Cash Flow

  $ 16.1   $ 36.9   $ 47.5  

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        The table below presents IXYS management's reconciliation of the non-GAAP prospective financial information included in the final management forecast to the most comparable GAAP financial measure for fiscal years 2018, 2019 and 2020.

 
  Fiscal Year Ending March 31,  
US$ in Millions
  2018E   2019E   2020E  

GAAP Cost of Revenue

  $ 231.9   $ 237.2   $ 244.6  

Stock-based compensation

    (0.4 )   (0.4 )   (0.5 )

Amortization of intangible assets

             

Non-GAAP Cost of Goods

  $ 231.5   $ 236.8   $ 244.1  

GAAP Gross Profit

  $ 119.3   $ 134.7   $ 150.1  

Stock-based compensation

    0.4     0.4     0.5  

Amortization of intangible assets

             

Non-GAAP Gross Profit

  $ 119.7   $ 135.1   $ 150.6  

GAAP Operating Expenses

  $ 77.2   $ 82.8   $ 87.1  

Stock-based compensation

    (3.3 )   (3.6 )   (4.0 )

Amortization of intangible assets

    (2.4 )   (0.6 )    

Non-GAAP Operating Expenses

  $ 71.5   $ 78.6   $ 83.1  

GAAP Operating Income

  $ 42.1   $ 51.8   $ 63.1  

Stock-based compensation

    3.7     4.0     4.4  

Amortization of intangible assets

    2.4     0.6      

Non-GAAP Operating Income

  $ 48.2   $ 56.4   $ 67.5  

GAAP Net Income

  $ 28.6   $ 36.4   $ 45.2  

Stock-based compensation (net of taxes)

    2.6     2.9     3.3  

Amortization of intangible assets

    2.4     0.6      

Non-GAAP Net Income

  $ 33.6   $ 40.0   $ 48.5  

Opinion of IXYS' Financial Advisor

        IXYS retained Needham & Company to act as IXYS' financial advisor in connection with the merger agreement and to render an opinion as to the fairness, from a financial point of view, to the holders of IXYS common stock (other than cancelled shares and dissenting shares) of the consideration to be received by those holders pursuant to the merger agreement.

        On August 25, 2017, Needham & Company delivered its oral opinion, which it subsequently confirmed in writing, to the IXYS board of directors that, as of that date and based upon and subject to the assumptions and other matters set forth in the written opinion, the consideration of $23.00 in cash or 0.1265 of a share of Littelfuse common stock per share of IXYS common stock to be received by the holders of IXYS common stock (other than holders of cancelled shares and dissenting shares) pursuant to the merger agreement was fair, from a financial point of view, to those holders. Needham & Company provided its opinion for the information and assistance of the IXYS board of directors in connection with and for the purpose of the IXYS board of directors' evaluation of the transactions contemplated by the merger agreement. Needham & Company's opinion relates only to the fairness, from a financial point of view, to the holders of IXYS common stock (other than holders of cancelled shares and dissenting shares) of the merger consideration, which was determined through arm's-length negotiations between IXYS and Littelfuse. While Needham & Company provided independent financial advice to the IXYS board of directors during the course of the negotiations between IXYS and Littelfuse, the decision to approve and recommend the merger was made

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independently by the IXYS board of directors. Needham & Company's opinion does not address any other aspect of the merger, or any related transaction, and does not constitute a recommendation to any stockholder of IXYS as to whether that stockholder should elect to receive the cash consideration or the stock consideration, or make no such election, or how that stockholder should vote or act on any matter relating to the merger. Needham & Company's opinion does not express any opinion as to the value of Littelfuse common stock when issued pursuant to the merger or the prices at which IXYS common stock or Littelfuse common stock will actually trade at any time.

        The complete text of Needham & Company's opinion, dated August 25, 2017, which sets forth the assumptions made, procedures followed, matters considered, and qualifications and limitations on and scope of the review undertaken by Needham & Company, is attached as Annex C to this proxy statement/prospectus. The summary of Needham & Company's opinion set forth below is qualified in its entirety by reference to the full text of the opinion. Holders of IXYS common stock should read this opinion carefully and in its entirety.

        In arriving at its opinion, Needham & Company, among other things:

    reviewed a draft of the merger agreement dated August 25, 2017;

    reviewed certain publicly available information concerning IXYS and Littelfuse and certain other relevant financial and operating data of IXYS and Littelfuse furnished to Needham & Company by IXYS and Littelfuse;

    reviewed the historical stock prices and trading volumes of the shares of IXYS common stock and Littelfuse common stock;

    held discussions with members of management of IXYS and Littelfuse concerning the current operations of and future business prospects for IXYS and Littelfuse and joint prospects for the combined companies, including the potential cost savings and other synergies that may be achieved by the combined companies;

    reviewed certain financial forecasts with respect to IXYS prepared by the management of IXYS and held discussions with members of such management concerning those forecasts;

    reviewed certain research analyst projections with respect to Littelfuse and held discussions with members of the management of Littelfuse concerning those projections;

    compared certain publicly available financial data of companies whose securities are traded in the public markets and that Needham & Company deemed generally relevant to similar data for IXYS and Littelfuse;

    reviewed the financial terms of certain business combinations that Needham & Company deemed generally relevant; and

    reviewed such other financial studies and analyses and considered such other matters as Needham & Company deemed appropriate.

        In connection with its review and in arriving at its opinion, Needham & Company assumed and relied on the accuracy and completeness of all of the financial, accounting, legal, tax and other information discussed with or reviewed by it for purposes of its opinion and did not independently verify, nor did Needham & Company assume responsibility for independent verification of, any of that information. Needham & Company assumed the accuracy of the representations and warranties contained in the merger agreement and all agreements related thereto. In addition, Needham & Company assumed that the merger will qualify as a reorganization within the meaning of Section 368(a) of the Internal Revenue Code of 1986 and that the merger will be consummated on the terms and subject to the conditions set forth in the draft merger agreement furnished to Needham & Company without waiver, modification or amendment of any material term, condition or agreement

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thereof and that, in the course of obtaining the necessary regulatory or third party approvals, consents and releases for the merger, no delay, limitation, restriction or condition will be imposed that would have an adverse effect on IXYS, Littelfuse or the contemplated benefits of the merger. Needham & Company assumed that the financial forecasts for IXYS provided to Needham & Company by management of IXYS were reasonably prepared on bases reflecting the best currently available estimates and judgments of such management, at the time of preparation, of the future operating and financial performance of IXYS. Needham & Company relied, without independent verification, upon the estimates of management of IXYS and Littelfuse of the potential cost savings and other synergies, including the amount and timing thereof, that may be achieved as a result of the merger. Needham & Company also assumed, based on discussions with the management of Littelfuse, that the research analyst projections for Littelfuse represent reasonable estimates of the future financial performance of Littelfuse. Needham & Company expressed no opinion with respect to any of those forecasts, (including those cost savings and other synergies), estimates or projections or the assumptions on which they were based.

        Needham & Company did not assume any responsibility for or make or obtain any independent evaluation, appraisal or physical inspection of the assets or liabilities of IXYS, Littelfuse or any of their respective subsidiaries, nor did Needham & Company evaluate the solvency or fair value of IXYS, Littelfuse or any of their respective subsidiaries under any state or federal laws relating to bankruptcy, insolvency or similar matters. Needham & Company's opinion states that it was based on economic, monetary and market conditions as they existed and could be evaluated as of its date, and Needham & Company assumed no responsibility to update or revise its opinion based upon circumstances and events occurring after its date. Needham & Company's opinion is limited to the fairness, from a financial point of view, to the holders of IXYS common stock (other than holders of cancelled shares and dissenting shares) of the merger consideration to be received by those holders pursuant to the merger agreement and Needham & Company expressed no opinion with respect to any other terms or aspects of the merger, including, without limitation, the form or structure of the merger, the form of the merger consideration, the allocation of the merger consideration as between holders of IXYS common stock who receive the stock consideration, the cash consideration or a combination thereof or the relative fairness of the stock consideration and the cash consideration. In addition, Needham & Company expressed no opinion as to the fairness of the merger to, or any consideration received in connection therewith by, the holders of any other class of securities, creditors or other constituencies of IXYS, or as to IXYS' underlying business decision to engage in the merger or the relative merits of the merger as compared to other business strategies that might be available to IXYS. Needham & Company also expressed no opinion with respect to the amount or nature or any other aspect of any compensation payable to or to be received by any officers, directors or employees of any party to the merger, or any class of those persons, relative to the consideration to be received by the holders of IXYS common stock pursuant to the merger agreement or with respect to the fairness of any such compensation.

        IXYS imposed no limitations on Needham & Company with respect to the investigations made or procedures followed by Needham & Company in rendering its opinion.

        In preparing its opinion, Needham & Company performed a variety of financial and comparative analyses. The following paragraphs summarize the material financial analyses performed by Needham & Company in arriving at its opinion. The order of analyses described does not represent relative importance or weight given to those analyses by Needham & Company. Some of the summaries of the financial analyses include information presented in tabular format. The tables are not intended to stand alone, and in order to more fully understand the financial analyses used by Needham & Company, the tables must be read together with the full text of each summary. The following quantitative information, to the extent it is based on market data, is, except as otherwise indicated, based on market data as they existed on or prior to August 25, 2017, and is not necessarily indicative of current or future market conditions.

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        IXYS Selected Companies Analysis.    Using publicly available information, Needham & Company compared selected historical and projected financial and market data and ratios for IXYS to the corresponding data and ratios of selected publicly traded companies that Needham & Company deemed relevant because they have lines of business that may be considered similar to certain lines of business of IXYS. The selected publicly traded companies, referred to as the selected companies, consisted of the following:

    Alpha and Omega Semiconductor Limited

    Diodes Incorporated

    Infineon Technologies AG

    Littelfuse, Inc.

    ON Semiconductor Corporation

    STMicroelectronics N.V.

    Vishay Intertechnology, Inc.

        The following table sets forth information concerning the following multiples for the selected companies and for IXYS implied by the merger:

    enterprise value as a multiple of last 12 months (referred to as LTM) revenues;

    enterprise value as a multiple of projected calendar year 2017 revenues;

    enterprise value as a multiple of projected calendar year 2018 revenues;

    enterprise value as a multiple of LTM earnings before interest, taxes, depreciation and amortization (referred to as adjusted EBITDA);

    enterprise value as a multiple of projected calendar year 2017 adjusted EBITDA;

    enterprise value as a multiple of projected calendar year 2018 adjusted EBITDA;

    price as a multiple of LTM non-GAAP earnings per share (referred to as non-GAAP EPS);

    price as a multiple of projected calendar year 2017 non-GAAP EPS; and

    price as a multiple of projected calendar year 2018 non-GAAP EPS.

        Needham & Company calculated multiples for the selected companies using consensus research analyst projections and the closing stock prices of those companies on August 25, 2017. Needham & Company calculated multiples for IXYS using IXYS management's forecasts and based on a merger consideration value of $23.00 per share. All financial information excluded the impact of non-recurring

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items. Adjusted EBITDA and non-GAAP EPS amounts excluded the impact of stock-based compensation expense.

 
  Selected Companies    
 
 
  IXYS Implied
by Merger
 
 
  75th Percentile   50th Percentile   25th Percentile  

Enterprise value to LTM revenues

    3.4x     1.9x     0.8x     2.2x  

Enterprise value to projected calendar year 2017 revenues

   
3.2x
   
1.7x
   
0.8x
   
2.1x
 

Enterprise value to projected calendar year 2018 revenues

   
2.9x
   
1.7x
   
0.8x
   
2.0x
 

Enterprise value to LTM adjusted EBITDA

   
13.1x
   
9.4x
   
5.6x
   
15.0x
 

Enterprise value to projected calendar year 2017 adjusted EBITDA

   
14.7x
   
9.7x
   
6.9x
   
13.6x
 

Enterprise value to projected calendar year 2018 adjusted EBITDA

   
11.1x
   
8.5x
   
6.1x
   
11.5x
 

Price to LTM non-GAAP EPS

   
24.7x
   
23.6x
   
16.0x
   
24.3x
 

Price to projected calendar year 2017 non-GAAP EPS

   
22.3x
   
20.6x
   
12.8x
   
21.6x
 

Price to projected calendar year 2018 non-GAAP EPS

   
18.9x
   
16.6x
   
12.4x
   
20.0x
 

        Selected Transactions Analysis.    Needham & Company reviewed publicly available financial information for the following selected merger and acquisition transactions, which represent the transactions completed since January 1, 2012 that involved target companies that were U.S. publicly traded semiconductor device companies with transaction equity values between $250 million and $1 billion:

Acquirer
  Target
MaxLinear, Inc.   Exar Corporation
MACOM Technology Solutions Holdings, Inc.   Applied Micro Circuits Corporation
Investor Consortium   Integrated Silicon Solution, Inc.
Diodes Incorporated   Pericom Semiconductor Corporation
Microchip Technology Incorporated   Micrel, Incorporated
Avago Technologies Limited   Emulex Corporation
MaxLinear, Inc.   Entropic Communications, Inc.
Microsemi Corporation   Vitesse Semiconductor Corporation
Lattice Semiconductor Corporation   Silicon Image, Inc.
Murata Electronics North America, Inc.   Peregrine Semiconductor Corporation
Cobham plc   Aeroflex Holdings Corp.
Avago Technologies Limited   PLX Technology, Inc.
Microchip Technology Incorporated   Supertex, Inc.
M/A-COM Technology Solutions Holdings, Inc.   Mindspeed Technologies, Inc.
Microsemi Corporation   Symmetricom, Inc.
Maxim Integrated Products, Inc.   Volterra Semiconductor Corporation
Microchip Technology Incorporated   Standard Microsystems Corporation
Skyworks Solutions, Inc.   Advanced Analogic Technologies Incorporated

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        In reviewing the selected transactions, Needham & Company calculated, for the selected transactions and for IXYS implied by the merger:

    enterprise value as a multiple of LTM revenues;

    enterprise value as a multiple of next twelve months (referred to as NTM) revenues;

    enterprise value as a multiple of LTM adjusted EBITDA; and

    enterprise value as a multiple of NTM adjusted EBITDA.

        Needham & Company calculated multiples for the selected transactions using consensus research analyst projections. Needham & Company calculated multiples for IXYS using IXYS management's forecasts and based on a merger consideration value of $23.00 per share.

        The following table sets forth information concerning the multiples described above for the selected transactions and the same multiples implied by the merger:

 
  Selected Transactions    
 
 
  IXYS Implied
by Merger
 
 
  75th Percentile   50th Percentile   25th Percentile  

Enterprise value to LTM revenues

    3.2x     2.2x     1.7x     2.2x  

Enterprise value to NTM revenues

   
3.0x
   
2.2x
   
1.8x
   
2.0x
 

Enterprise value to LTM adjusted EBITDA

   
20.0x
   
15.4x
   
11.6x
   
15.0x
 

Enterprise value to NTM adjusted EBITDA

   
21.8x
   
16.7x
   
10.8x
   
12.1x
 

        Premiums Paid Analysis.    Needham & Company reviewed publicly available financial information for 14 merger and acquisition transactions that represent the transactions completed since January 1, 2012 involving a combination of stock and cash consideration and U.S. publicly traded technology companies with transaction equity values of between $250 million and $1.5 billion. In examining these transactions, Needham & Company analyzed the premium of consideration offered to the acquired company's stock price one day, five days, 30 days and 90 days prior to the announcement of the transaction.

        Needham & Company calculated premiums for IXYS based on a merger consideration value of $23.00 per share and the closing prices per share of IXYS common stock one day, five days, 30 days and 90 days prior to August 25, 2017. The following table sets forth information concerning the stock price premiums in the selected transactions and the stock price premiums implied by the merger:

 
  Selected Transactions    
 
 
  IXYS Implied
by Merger
 
 
  75th Percentile   50th Percentile   25th Percentile  

One day stock price premium

    41.6 %   28.4 %   13.7 %   44.2 %

Five day stock price premium

   
45.5

%
 
26.8

%
 
12.6

%
 
45.6

%

30 day stock price premium

   
47.2

%
 
29.0

%
 
22.8

%
 
34.1

%

90 day stock price premium

   
68.4

%
 
37.2

%
 
18.0

%
 
65.5

%

        Needham & Company reviewed publicly available financial information for 25 merger and acquisition transactions that represent the transactions completed since January 1, 2016 involving all cash consideration and U.S. publicly traded technology companies with transaction equity values of between $250 million and $1.5 billion. In examining these transactions, Needham & Company analyzed the premium of consideration offered to the acquired company's stock price one day, five days, 30 days and 90 days prior to the announcement of the transaction.

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        Needham & Company calculated premiums for IXYS based on a merger consideration value of $23.00 per share and the closing prices per share of IXYS common stock one day, five days, 30 days and 90 days prior to August 25, 2017. The following table sets forth information concerning the stock price premiums in the selected transactions and the stock price premiums implied by the merger:

 
  Selected Transactions    
 
 
  IXYS Implied
by Merger
 
 
  75th Percentile   50th Percentile   25th Percentile  

One day stock price premium

    37.4 %   29.6 %   19.2 %   44.2 %

Five day stock price premium

   
39.6

%
 
33.3

%
 
17.2

%
 
45.6

%

30 day stock price premium

   
50.4

%
 
37.0

%
 
21.3

%
 
34.1

%

90 day stock price premium

   
58.6

%
 
31.9

%
 
16.4

%
 
65.5

%

        Discounted Cash Flow Analysis.    Needham & Company performed an illustrative discounted cash flow analysis based on IXYS management's forecasts to determine indicators of illustrative implied equity values for IXYS and illustrative implied equity values per share of common stock. Needham & Company calculated a range of indications of the present value of unlevered free cash flows for IXYS for the projected six months ending March 31, 2018 and projected fiscal years ending March 31, 2019 and 2020 using discount rates ranging from 11.5% to 13.5%. The range of discount rates, reflecting an estimated range of weighted average costs of capital of IXYS, was selected by Needham & Company utilizing its professional judgment and experience. Needham & Company then calculated a range of illustrative terminal enterprise values at the end of the fiscal year ending March 31, 2020 by applying multiples ranging from 7.0x to 10.0x to IXYS management's estimate of its fiscal year 2020 adjusted EBITDA. The range of multiples was selected by Needham & Company utilizing its professional judgment and experience. These illustrative terminal enterprise values were then discounted to calculate ranges of implied indications of present values using the same range of discount rates, 11.5% to 13.5%, as described above. Needham & Company then added the ranges of the implied present values of IXYS' unlevered free cash flows for the projected periods to the ranges of implied present values of IXYS' terminal enterprise values to derive ranges of implied present enterprise values of IXYS. Needham & Company then added IXYS' cash and subtracted IXYS' debt (including the unfunded portion of pension obligations) as of June 30, 2017, to arrive at the ranges of illustrative implied present equity values. Needham & Company calculated the number of IXYS' estimated fully-diluted shares outstanding at the end of the fiscal year ending March 31, 2020 based on IXYS management's estimates of 2.0% annual future share dilution to current stockholders resulting from issuances of equity compensation awards, and divided the implied present equity values by this estimated fully-diluted outstanding share number. This analysis indicated an illustrative implied per share equity reference range for IXYS of $15.22 to $20.65.

        Present Value of Illustrative Future Stock Prices Analysis.    Needham & Company performed an illustrative analysis of the implied present value of the future price per share of IXYS common stock, which is designed to provide an indication of the present value of a theoretical future value of a company's equity.

        For this analysis, Needham & Company used IXYS management's forecasts. Needham & Company calculated the illustrative implied enterprise value for IXYS for each of the projected fiscal years 2018, 2019 and 2020 by applying illustrative multiples ranging from 7.0x to 10.0x to IXYS' projected fiscal year ending March 31, 2018, 2019 and 2020 adjusted EBITDA. The range of illustrative multiples was selected by Needham & Company utilizing its professional judgment and experience. Then Needham & Company added IXYS' projected cash and subtracted IXYS' projected debt (including the unfunded portion of pension obligations) at the end of the respective projected fiscal years 2018, 2019 and 2020 to derive ranges of implied equity values, and divided these implied equity values by the respective

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numbers of projected fiscal year end fully-diluted outstanding shares to calculate ranges of implied future equity values per share of common stock for those fiscal years. The assumed number of fully-diluted shares at the end of each projected fiscal year was based on IXYS management's estimates of 2.0% annual future share dilution to current stockholders resulting from issuances of equity compensation awards. Needham & Company then in each case discounted these implied equity values per share back to August 25, 2017 using discount rates ranging from 13.1% to 15.1%. The range of discount rates, reflecting an estimated range of IXYS' cost of equity, was selected by Needham & Company utilizing its professional judgment and experience. This analysis resulted in a range of implied present values per share of $13.16 to $19.26.

        Littelfuse Selected Companies Analysis.    Using publicly available information, Needham & Company compared selected historical and projected financial and market data ratios for Littelfuse to the corresponding data and ratios of the selected companies other than Littelfuse.

        The following table sets forth information concerning the following multiples for the selected companies other than Littelfuse and for Littelfuse:

    enterprise value as a multiple of LTM revenues;

    enterprise value as a multiple of projected calendar year 2017 revenues;

    enterprise value as a multiple of projected calendar year 2018 revenues;

    enterprise value as a multiple of LTM EBITDA;

    enterprise value as a multiple of projected calendar year 2017 adjusted EBITDA;

    enterprise value as a multiple of projected calendar year 2018 adjusted EBITDA;

    price as a multiple of non-GAAP LTM EPS;

    price as a multiple of non-GAAP projected calendar year 2017 EPS; and

    price as a multiple of non-GAAP projected calendar year 2018 EPS.

        Needham & Company calculated multiples for the selected companies other than Littelfuse using consensus research analyst estimates and based on the closing stock prices of those companies on August 25, 2017. Needham & Company calculated multiples for Littelfuse using consensus analyst estimates from analysts and research reports identified by Littelfuse management for use in analysis and based on the closing stock price of Littelfuse common stock on August 25, 2017. All financial

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information excluded the impact of non-recurring items. Adjusted EBITDA and non-GAAP EPS amounts excluded the impact of stock-based compensation expense.

 
  Selected Companies Other than Littelfuse    
 
 
  75th Percentile   50th Percentile   25th Percentile   Littelfuse  

Enterprise value to LTM revenues

    2.4x     1.7x     0.8x     3.7x  

Enterprise value to projected calendar year 2017 revenues

   
2.2x
   
1.6x
   
0.8x
   
3.5x
 

Enterprise value to projected calendar year 2018 revenues

   
2.0x
   
1.5x
   
0.8x
   
3.3x
 

Enterprise value to LTM adjusted EBITDA

   
12.3x
   
8.9x
   
5.4x
   
16.0x
 

Enterprise value to projected calendar year 2017 adjusted EBITDA

   
13.2x
   
7.9x
   
6.0x
   
14.6x
 

Enterprise value to projected calendar year 2018 adjusted EBITDA

   
10.0x
   
7.3x
   
5.5x
   
13.6x
 

Price to non-GAAP LTM EPS

   
26.2x
   
21.0x
   
15.6x
   
24.7x
 

Price to projected calendar year 2017 non-GAAP EPS

   
21.3x
   
18.1x
   
12.5x
   
23.2x
 

Price to projected calendar year 2018 non-GAAP EPS

   
17.9x
   
15.3x
   
11.8x
   
21.3x
 

        Pro Forma Transaction Analysis.    Needham & Company prepared pro forma analyses of the financial impact of the merger based on the merger consideration, estimated financial results of IXYS and Littelfuse for calendar year 2018, and an assumption of projected cost savings and other synergies resulting from the merger. The estimated financial results for IXYS were based upon IXYS management's estimates and the estimated financial results for Littelfuse were based on consensus analyst estimates from analysts and research reports identified by Littelfuse management for use in analysis. The estimated cost savings and other synergies, aggregating $15.0 million in calendar year 2018, were based on Littelfuse management's estimates. Based upon these estimates and assumptions, Needham & Company noted that the merger would result in accretion to the estimated adjusted EPS of Littelfuse for calendar year 2018, which excludes the impact of non-recurring items but includes stock-based compensation as an expense. The actual operating or financial results achieved by the combined entity may vary from estimated results, and these variations may be material.

        No company, transaction or business used in the "IXYS Selected Companies Analysis," "Selected Transactions Analysis," "Premiums Paid Analysis" or "Littelfuse Selected Companies Analysis" as a comparison is identical to IXYS or Littelfuse or to the merger. Accordingly, an evaluation of the results of these analyses is not entirely mathematical; rather, it involves complex considerations and judgments concerning differences in the financial and operating characteristics and other factors that could affect the acquisition, public trading or other values of the selected companies or selected transactions or the business segment, company or transaction to which they are being compared.

        The summary set forth above does not purport to be a complete description of the analyses performed by Needham & Company in connection with the rendering of its opinion. The preparation of a fairness opinion is a complex analytical process involving various determinations as to the most appropriate and relevant quantitative and qualitative methods of financial analyses and the application of those methods to the particular circumstances and, therefore, such an opinion is not readily susceptible to summary description. Accordingly, Needham & Company believes that its analyses must

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be considered as a whole and that selecting portions of its analyses or the factors that it considered, without considering all analyses and factors, could create a misleading or incomplete view of the process underlying its analyses and opinion. Needham & Company did not attribute any specific weight to any factor or analysis considered by it. The fact that any specific analysis has been referred to in the summary above is not meant to indicate that such analysis was given greater weight than any other analysis.

        In performing its analyses, Needham & Company made numerous assumptions with respect to industry performance, general business and economic conditions and other matters, many of which are beyond the control of IXYS or Littelfuse. Any estimates contained in or underlying these analyses, including estimates of IXYS' or Littelfuse's future performance, are not necessarily indicative of actual values or predictive of future results or values, which may be significantly more or less favorable than those estimates. Additionally, analyses relating to the values of businesses or assets do not purport to be appraisals or necessarily reflect the prices at which businesses or assets may actually be sold or the prices at which any securities have traded or may trade at any time in the future. Accordingly, these analyses and estimates are inherently subject to substantial uncertainty. Needham & Company's opinion and its related analyses were only one of many factors considered by the members of the IXYS board of directors in their evaluation of the merger and should not be viewed as determinative of the views of the IXYS board of directors or management with respect to the merger consideration or the merger.

        Under the terms of its engagement letter with Needham & Company, IXYS has paid or agreed to pay Needham & Company a nonrefundable fee of $600,000 that became payable upon Needham & Company's delivery of its opinion on August 25, 2017. If the merger is consummated, IXYS has agreed to pay Needham & Company an additional fee estimated to be approximately $8 million. Whether or not the merger is consummated, IXYS has agreed to reimburse Needham & Company for certain of its out-of-pocket expenses and to indemnify Needham & Company and related persons against various liabilities, including certain liabilities under the federal securities laws.

        Needham & Company is a nationally recognized investment banking firm. As part of its investment banking services, Needham & Company is regularly engaged in the valuation of businesses and their securities in connection with mergers and acquisitions, negotiated underwritings, secondary distributions of securities, private placements and other purposes. Needham & Company believes that it was retained by the IXYS board of directors as IXYS' financial advisor in connection with the merger based on Needham & Company's experience as a financial advisor in mergers and acquisitions as well as Needham & Company's familiarity with IXYS and its industry generally. Needham & Company has not in the past two years provided investment banking or financial advisory services to IXYS unrelated to its current engagement with respect to the proposed transaction for which it has received or is entitled to receive compensation. Needham & Company has not in the past two years provided investment banking or financial advisory services to Littelfuse or Merger Sub for which it has received or is entitled to receive compensation. Needham & Company may in the future provide investment banking and financial advisory services to IXYS, Littelfuse and their respective affiliates unrelated to the merger, for which services Needham & Company would expect to receive compensation. In the normal course of its business, Needham & Company may actively trade equity securities of IXYS and Littelfuse for its own account or for the accounts of its customers or affiliates and, therefore, may at any time hold a long or short position in those securities.

Form of Merger

        Under the terms of the merger agreement, IXYS has agreed to be acquired by Littelfuse. If the merger agreement is adopted by IXYS stockholders and the other conditions to closing under the merger agreement are satisfied or waived, Merger Sub will merge with and into IXYS, with IXYS continuing as the surviving corporation in the initial merger and a wholly owned subsidiary of Littelfuse. Further to the terms of the merger agreement, IXYS, as the surviving corporation of the

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initial merger, will merge with and into Littelfuse (or a subsidiary of Littelfuse), with Littelfuse (or such subsidiary) continuing as the surviving corporation in the follow-on merger. Littelfuse intends to structure the follow-on merger as a merger of IXYS with and into a subsidiary of Littelfuse.

Interests of IXYS' Directors and Executive Officers in the Merger

        When considering the recommendation of the IXYS board of directors with respect to the merger, you should be aware that IXYS' directors and executive officers may have interests in the merger that are different from, or in addition to, those of IXYS stockholders more generally. The IXYS board of directors was aware of these interests during its deliberations on the merits of the merger and considered them in deciding to recommend that IXYS stockholders vote to adopt the merger agreement.

        As described below, the interests of IXYS' non-employee directors and executive officers include the following:

    accelerated vesting of 100% of the outstanding and unexercised stock options held by each non-employee director and executive officer upon the effective time;

    a seat on Littelfuse's board of directors for Dr. Zommer following the effective time;

    amended and restated employment agreements between IXYS and each executive officer, which will become effective upon the consummation of the merger, as described in more detail below under "—Employment Agreements with Executive Officers";

    in the event of certain qualifying terminations of employment upon or following the effective time, each executive officer will be entitled to receive certain severance payments and benefits, as described in more detail under "—Employment Agreements with Executive Officers"; and

    the right to indemnification and liability insurance coverage that will survive the completion of the merger.

Treatment of IXYS Stock Options in the Merger

        As described below in the section titled "The Merger Agreement—Treatment of IXYS Stock Options," at the effective time, each outstanding and unexercised IXYS stock option will be assumed by Littelfuse and converted into a Littelfuse stock option to acquire (i) that number of whole shares of Littelfuse common stock (rounded down to the nearest whole share) equal to the product of (x) the number of shares of IXYS common stock subject to such IXYS stock option immediately prior to the effective time multiplied by (y) 0.1265, (ii) at an exercise price per share of Littelfuse common stock (rounded up to the nearest whole cent) equal to the quotient of (x) the exercise price per share of IXYS common stock of such IXYS stock option divided by (y) 0.1265. Each IXYS stock option assumed and converted into a Littelfuse stock option will continue to have, and will be subject to, the same vesting schedule (including any accelerated vesting terms) and all other terms and conditions as applied to such IXYS stock option immediately prior to the effective time.

        As described below under "—Employment Agreements with Executive Officers," pursuant to the terms of their amended and restated employment agreements with IXYS, which will become effective upon the consummation of the merger, any outstanding and unexercised stock options held by Dr. Zommer and Mr. Sasson will vest and become exercisable in full upon the effective time. Additionally, any outstanding and unexercised stock options held by IXYS' non-employee directors will vest and become exercisable upon the effective time in accordance with their terms.

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        The table below shows the number of outstanding, unexercised and unvested stock options that are held by such individuals as of October 16, 2017 and the aggregate intrinsic values of such unvested stock options. In accordance with applicable SEC rules, the dollar values below are based on a per share price of IXYS common stock of $22.69, which is the average closing price of IXYS common stock on The NASDAQ Global Select Market over the first five business days following the first public announcement of the merger on August 28 2017. The actual value of any executive officer's or non-employee director's unvested stock options as of the closing below will depend on the number of shares of IXYS common stock underlying outstanding and unvested stock options held by such individuals as of the closing and, accordingly, may differ from the values set forth below.

 
  Number of Shares of IXYS
Common Stock Subject to
Unvested Stock Options (#)
  Aggregate Intrinsic Value of
Unvested Stock Options ($)
 

Executive Officers

             

Nathan Zommer

    7,500     84,113  

Uzi Sasson

    162,500     1,820,175  

Non-Employee Directors

             

Donald L. Feucht

    7,500     84,113  

Samuel Kory

    7,500     84,113  

S. Joon Lee

    7,500     84,113  

Timothy A. Richardson

    7,500     84,113  

James M. Thorburn

    7,500     84,113  

Kenneth D. Wong

    7,500     84,113  

Littelfuse Board of Directors Following the Merger

        Pursuant to the merger agreement, Littelfuse has agreed to cause the number of directors that will comprise the Littelfuse board of directors as of the effective time to be increased by one member. Dr. Zommer will join the board of directors of Littelfuse, subject to his completion of the requisite documentation.

Amended Employment Agreements with Executive Officers

        On August 25, 2017, IXYS entered into (i) a Seventh Amended Executive Employment Agreement with Dr. Zommer pursuant to which he will serve as IXYS' Chief Executive Officer, and (ii) a Fourth Amended Executive Employment Agreement with Mr. Sasson pursuant to which he will serve as IXYS' President, Chief Executive Officer and Chief Financial Officer (collectively referred to herein as the amended employment agreements), each of which will become effective upon the occurrence of a "change in control" (as defined in IXYS' 2016 Equity Incentive Plan or any successor thereto) occurring on or prior to December 31, 2018. The amended employment agreements are expected to become effective upon the closing of the merger (provided that the merger closes on or prior to December 31, 2018) and, upon their effectiveness, the amended employment agreements will amend and restate the existing employment agreements for Dr. Zommer and Mr. Sasson in their entirety.

        Each amended employment agreement has an initial three-year term ending on the third anniversary of the effective date of such agreement, and will automatically be extended for successive one-year periods thereafter unless either party elects not to renew the term of the amended employment agreement by notifying the other party in writing of such election at least 90 days prior to the commencement of any renewal period.

        Pursuant to the amended employment agreement, Dr. Zommer and Mr. Sasson (together, the "executive officers") will receive an annual base salary of $525,000 and $450,000, respectively, which is subject to increase, but not decrease, in IXYS' discretion. Each executive officer will be eligible for a

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discretionary annual performance bonus and for stock options, restricted stock and/or other equity award grants in the discretion of the IXYS board of directors. The executive officers will be eligible to participate in IXYS' retirement, health and welfare benefit plans and programs generally made available to IXYS' similarly situated executives from time to time. Pursuant to their respective amended employment agreement, the executive officers will also entitled to (i) payment or reimbursement for reasonable costs of a yearly medical exam, (ii) IXYS-maintained life insurance, (iii) payment or reimbursement for personal tax and/or investment advisor services (capped at $2,000 per year), and (iv) either (A) an IXYS-provided car and reimbursement for the costs incurred in connection with the use of such car for business purposes or (B) payment of a monthly car allowance (collectively, the "employment benefits").

        Each amended employment agreement provides that if the applicable executive officer's employment with IXYS is terminated by IXYS without "cause," by such executive officer for "good reason" or due to a non-renewal of the term of the amended employment agreement by IXYS (provided that the executive officer is willing and able to continue his employment on similar terms and conditions at such time), then, subject to the executive officer's execution and non-revocation of a general release of claims, the executive officer will be entitled to receive the following payments and benefits: (i) a lump-sum payment equal to three times the executive officer's average annual cash compensation over the three prior years, payable within 60 days following termination; (ii) continued provision of employee benefits (including the employment benefits) (or their cash equivalent) for 18 months following termination; and (iii) accelerated vesting of all stock options and other equity awards then-held by the executive officer.

        In the event of the applicable executive officer's "disability" (as defined in the amended employment agreement), the executive officer will be entitled to (i) continued payment of his base salary for 18 months, and (ii) IXYS-provided health insurance (or its cash equivalent) and life insurance benefits for 18 months.

        Each employment agreement provides that, upon a "change in control" of IXYS, which will include the merger, all stock options, restricted stock awards, stock appreciation rights or other stock rights granted to the executive officer by IXYS will vest in full (to the extent then-unvested).

        To the extent that any payment, distribution or other benefit provided by IXYS to or for the benefit of the applicable executive officer in connection with a change in control would be subject to an excise tax under Section 4999 of the Code, such payments, distributions and/or benefits will be subject to a "best pay cap" reduction if such reduction would result in a greater net after-tax benefit to the executive officer than receiving the full amount of such payments.

        See the section entitled "—Quantification of Potential Payments and Benefits to IXYS' Named Executive Officers in Connection with the Merger" below for an estimate of the value of the payments and benefits that Dr. Zommer and Mr. Sasson may become entitled to receive at the effective time and upon a qualifying termination of employment at or following the effective time.

Indemnification and Insurance

        The merger agreement provides that all rights to indemnification and exculpation from liabilities for acts or omissions occurring at or prior to the effective time in favor of certain indemnified parties, including the directors and executive officers of IXYS, will survive the merger and continue in full force and effect in accordance with their terms, as set forth in the IXYS organizational documents or any indemnification agreements in existence upon execution of the merger agreement, for six years following the effective time.

        Following the effective time, the surviving corporation will, and Littelfuse will cause the surviving corporation to, indemnify and hold harmless each IXYS indemnified party against any cost or expense

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arising out of the fact that such person is or was a director or officer of IXYS or any of its subsidiaries or other fiduciary in any entity at the request or for the benefit of IXYS and pertaining to matters existing or occurring prior to the effective time (including with respect to the merger and merger agreement), to the fullest extent permitted by applicable law.

        The merger agreement requires Littelfuse to cause the surviving corporation to maintain, for a period of six years after the effective time, IXYS' existing directors' and officers' liability insurance policy, or substantially comparable insurance of at least the same coverage and amounts containing terms and conditions which are no less advantageous to the insured.

        For a more detailed description of the provisions of the merger agreement relating to director and officer indemnification and liability insurance, please see the section of this proxy statement/prospectus entitled "The Merger Agreement—Indemnification and Insurance."

Quantification of Potential Payments and Benefits to IXYS' Named Executive Officers in Connection with the Merger

        The information set forth in the table below is intended to comply with Item 402(t) of the SEC's Regulation S-K, which requires disclosure of information about the compensation that is payable or that may become payable to each named executive officer of IXYS that is based on, or otherwise relates to, the merger. For additional details regarding the terms of the payments and benefits described below, see the discussion under the caption "—Interests of IXYS' Directors and Executive Officers in the Merger" above.

        The amounts shown in the table below are estimates based on multiple assumptions that may or may not actually occur or be accurate on the relevant date, including the assumptions described below and in the footnotes to the table. As a result, the amount, if any, that a named executive officer actually receives in the merger may materially differ from the amounts set forth in the table. For purposes of calculating the amounts set forth in the table, the following assumptions were used:

    A per share price of IXYS common stock of $22.69, which is the average closing price of IXYS common stock on The NASDAQ Global Select Market over the first five business days following the first public announcement of the merger on August 28, 2017;

    The effective time of the merger is October 16, 2017;

    Each of Dr. Zommer's and Mr. Sasson's employment was terminated either by IXYS without "cause" or by the executive for "good reason" (as such terms are defined in the amended employment agreements), in either case, on or immediately following the effective time; and

    Quantification of the accelerated vesting of stock options is calculated based on the outstanding, unexercised and unvested stock options held by the named executive officer as of October 16, 2017.

Golden Parachute Compensation

Executive Officers
  Cash(1)
($)
  Equity(2)
($)
  Perquisites/
Benefits(3)
($)
  Total(4)
($)
 

Nathan Zommer

    2,127,778     84,113     29,547     2,241,438  

Uzi Sasson

    2,114,784     1,820,175     51,825     3,986,784  

(1)
The estimated amounts listed in this column represent the "double-trigger" (i.e., amounts triggered by a change in control for which payment is conditioned upon the executive officer's termination without cause or resignation for good reason following the change in control) cash severance

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    payments that the executive officers would be entitled to receive upon a termination of employment by IXYS without cause or by the executive officer for good reason, in each case, assuming such termination occurred at or immediately following the effective time. The cash severance amounts represent an amount equal to three times the executive officer's average annual cash compensation over the three prior years. The cash severance is payable in a lump sum within 60 days following the date of termination. As a condition to receipt of such payments, the executive officers are required to timely execute and not revoke a general release of claims.

    For additional information regarding these amounts, see the section titled "—Interests of IXYS' Directors and Executive Officers in the Merger" beginning on page 74 of this proxy statement/prospectus.

(2)
The estimated amounts listed in this column represent the aggregate intrinsic value of each executive officer's outstanding, unexercised and unvested stock options that will accelerate as of the effective time pursuant to the applicable executive officer's amended employment agreement. Such benefit is "single-trigger" (i.e., an amount triggered by a change in control for which payment is not conditioned upon a termination or resignation of the executive officer).

For additional information regarding the named executive officers' rights to accelerated vesting of stock options, see the section titled "—Interests of IXYS' Directors and Executive Officers in the Merger" beginning on page 74 of this proxy statement/prospectus.

(3)
The amounts listed in this column represent the estimated value of the "double-trigger" continued employment benefits that the executive officers would be entitled to for up to 18 months following the executive officer's qualifying termination of employment following the effective time.

For additional information regarding these amounts, see the section titled "—Interests of IXYS' Directors and Executive Officers in the Merger" beginning on page 74 of this proxy statement/prospectus.

(4)
Each amended employment agreement includes a Code Section 280G "best pay" cutback, such that if any payments or benefits that an executive officer is entitled to receive under his Employment Agreement or otherwise would constitute a "parachute payment" under Section 280G of the Code and would be subject to the excise tax imposed by Section 4999 of the Code, the aggregate payments and benefits will either be delivered in full or delivered in a lesser amount that would result in no portion of the aggregate payments and benefits being subject to the excise tax, whichever results in the receipt by the executive officer of the greatest amount of aggregate payments and benefits on an after-tax basis. However, for purposes of this disclosure and the table set forth above, IXYS has not taken into account any potential reduction in payments or benefits as a result of the "best pay" cutback provision and, accordingly, has disclosed the full value of each executive officer's payments and benefits.

Narrative Disclosure to Golden Parachute Compensation Table

        Each of the executive officers holds outstanding, unexercised and unvested stock options to purchase shares of IXYS common stock that will vest and become exercisable, and will be assumed by Littelfuse and converted into options to purchase shares of Littelfuse common stock, upon the closing of the merger. For more information related to the treatment of such stock options in connection with the merger, see the footnote disclosures above and the section titled "—Interests of IXYS' Directors and Executive Officers in the Merger" beginning on page 74 of this proxy statement/prospectus.

        IXYS is a party to an amended employment agreement with each of the executive officers, which are expected to become effective upon the closing of the merger, each of which provides for severance payments and benefits upon a qualifying termination of the executive officer's employment or upon a non-renewal of the term of the amended employment agreement by IXYS. For more information

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related to these amended employment agreements, see the footnote disclosures above and the section titled "—Interests of IXYS' Directors and Executive Officers in the Merger" beginning on page 74 of this proxy statement/prospectus.

Accounting Treatment of the Merger

        Littelfuse prepares its financial statements in accordance with GAAP. The merger will be accounted for using the acquisition method of accounting. Littelfuse will be treated as the acquiror for accounting purposes. Littelfuse will record assets acquired, including identifiable intangible assets, and liabilities assumed from IXYS at their respective fair values at the date of completion of the merger. Any excess of the purchase price (as described under Note 1—"Basis of Pro Forma Presentation" under "Unaudited Pro Forma Condensed Combined Financial Information—Notes to Unaudited Pro Forma Condensed Combined Financial Information" beginning on page 118) over the net fair value of such assets and liabilities will be recorded as goodwill.

        The financial condition and results of operations of Littelfuse after completion of the merger will reflect IXYS after completion of the merger, but will not be restated retroactively to reflect the historical financial condition or results of operations of IXYS. The earnings of Littelfuse following completion of the merger will reflect acquisition accounting adjustments, including the effect of changes in the carrying value for assets and liabilities on depreciation expense, amortization expense and interest expense. Indefinite-lived intangible assets, including certain trademarks, and goodwill will not be amortized but will be tested for impairment at least annually, and all tangible and intangible assets including goodwill will be tested for impairment when certain indicators are present. If, in the future, Littelfuse determines that tangible or intangible assets (including goodwill) are impaired, Littelfuse would record an impairment charge at that time.

Material U.S. Federal Income Tax Consequences

        The following general discussion addresses the material U.S. federal income tax consequences to U.S. holders (as defined below) of IXYS common stock that exchange their IXYS common stock for the merger consideration in the initial merger. The discussion is based on the Code, Treasury regulations, administrative rulings, published positions of the Internal Revenue Service (referred to in this proxy statement/prospectus as the IRS) and judicial decisions, all as currently in effect and all of which are subject to change and to differing interpretations (possibly with retroactive effect), and any such change or interpretation could affect the accuracy of the statements and conclusions set forth in this discussion. This discussion applies only to U.S. holders (as defined below) that hold their IXYS common stock as a capital asset within the meaning of Section 1221 of the Code (generally, property held for investment). This discussion does not address all aspects of U.S. federal taxation that may be relevant to a particular stockholder in light of his, her or its individual circumstances or to stockholders subject to special treatment under U.S. federal income tax laws, including:

    banks or other financial institutions,

    trusts,

    tax exempt organizations,

    governmental agencies or instrumentalities,

    insurance companies,

    dealers in securities or foreign currency,

    traders in securities who elect to apply a mark-to-market method of accounting,

    mutual funds,

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    partnerships or other pass-through entities for U.S. federal income tax purposes and investors in such entities,

    foreign persons,

    certain expatriates,

    holders that exercise appraisal rights,

    regulated investment companies and real estate investment trusts,

    broker-dealers,

    holders liable for the alternative minimum tax,

    holders that have a functional currency other than the U.S. dollar,

    holders who received their IXYS common stock through the exercise of employee stock options, through a tax-qualified retirement plan or otherwise as compensation,

    holders that exercise dissenters' rights,

    holders that hold (or that held, directly or constructively, at any time during the five-year period ending on the date of the disposition of such holder's IXYS common stock pursuant to the initial merger) 5% or more of the IXYS common stock, and

    holders who hold IXYS common stock (or, after the initial merger, Littelfuse common stock) as part of a hedge, straddle, constructive sale, conversion transaction or other integrated investment.

        In addition, the discussion does not address any state, local or foreign tax consequences of the merger, nor does it address the impact of the Medicare contribution tax on net investment income or any U.S. federal laws other than those pertaining to the U.S. federal income tax.

        For purposes of this discussion, a "U.S. holder" or "holder" is a beneficial owner of IXYS common stock who is, for U.S. federal income tax purposes:

    (i)
    an individual who is a citizen or resident of the United States;

    (ii)
    a corporation or other entity taxable as a corporation, created or organized under the laws of the United States, any state thereof, or the District of Columbia;

    (iii)
    an estate that is subject to U.S. federal income tax on its income regardless of its source; or

    (iv)
    a trust that (A) is subject to the primary supervision of a court within the United States and all substantial decisions of which are subject to the control of one or more "United States persons" (within the meaning of Section 7701(a)(30) of the Code) or (B) has a valid election in effect to be treated as a United States person for U.S. federal income tax purposes.

        If a partnership, including any entity or arrangement treated as a partnership for U.S. federal income tax purposes, holds shares of IXYS common stock, the U.S. federal income tax treatment of a partner in such partnership will generally depend upon the status of the partner and the activities of the partnership. Accordingly, such partners and partnerships should consult their tax advisors regarding the particular tax consequences of the merger to them.

        Each holder of IXYS common stock should consult his, her or its tax advisor with respect to the particular tax consequences of the merger to such holder.

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Tax Consequences of the Merger Generally

        The completion of the merger is conditioned upon the delivery by each of Wachtell, Lipton, Rosen & Katz (or other nationally recognized outside counsel), counsel to Littelfuse, and Latham & Watkins LLP (or other nationally recognized outside counsel), counsel to IXYS, of its opinion to the effect that the initial merger and the follow-on merger, taken together, will qualify as a "reorganization" within the meaning of Section 368(a) of the Code. If the initial merger and the follow-on merger, taken together, qualify as a "reorganization" within the meaning of Section 368(a) of the Code, the U.S. federal income tax consequences to U.S. holders who receive stock consideration and/or cash consideration in exchange for their shares of IXYS common stock pursuant to the merger agreement generally will be as described below. The opinions of counsel will be based on factual representations contained in letters provided by Littelfuse and IXYS, and on certain customary factual assumptions, all of which must continue to be true and accurate as of the consummation of the merger. These opinions are not binding on the IRS or the courts, and neither Littelfuse nor IXYS intends to request a ruling from the IRS regarding the U.S. federal income tax consequences of the merger. Consequently, no assurance can be given that the IRS will not assert, or that a court would not sustain, a position contrary to any of those set forth below.

        The U.S. federal income tax consequences of the merger to a holder generally will depend on whether the holder exchanges its IXYS common stock for cash consideration, stock consideration or a combination of cash consideration and stock consideration.

Exchange Solely for Cash

        The exchange of shares of IXYS common stock solely for cash consideration generally will result in the recognition of gain or loss equal to the difference between the amount of cash consideration received and the holder's adjusted tax basis in the shares of IXYS common stock surrendered, which gain or loss generally will be long-term capital gain or loss if the holder's holding period with respect to the IXYS common stock surrendered is more than one year at the effective time. The deductibility of capital losses is subject to limitations. In some cases, if a holder actually or constructively owns Littelfuse common stock after the merger, the cash consideration received could be treated as having the effect of a distribution of a dividend under the tests set forth in Section 302 of the Code, in which case such holder may have dividend income up to the amount of the cash consideration received. Because the possibility of dividend treatment depends primarily upon the particular circumstances of a holder, including the application of certain constructive ownership rules, holders should consult their tax advisors regarding the potential tax consequences of the merger to them, and holders that are corporations should consult their tax advisors regarding the potential applicability of the "extraordinary dividend" provisions of the Code.

        Holders electing to receive the all-cash consideration in the initial merger may be subject to proration (see the section titled "The Merger—Merger Consideration"), which may result in the receipt of a portion of the merger consideration in stock consideration, in addition to cash consideration. See the section titled "—Exchange for Littelfuse Common Stock and Cash" for a general description of the U.S. federal income tax consequences to holders of the receipt of stock consideration and cash consideration.

Exchange Solely for Littelfuse Common Stock

        If, pursuant to the initial merger, a holder exchanges all of its shares of IXYS common stock solely for stock consideration, that holder generally will not recognize any gain or loss, except in respect of cash in lieu of a fractional share of Littelfuse common stock (as discussed in the section titled "—Cash in Lieu of a Fractional Share"). The aggregate adjusted tax basis of the stock consideration received in the initial merger (including fractional shares deemed received and redeemed as described below) will

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be equal to the aggregate adjusted tax basis of the shares of IXYS common stock surrendered, and the holding period of the stock consideration (including fractional shares deemed received and redeemed as described in the section titled "—Cash in Lieu of a Fractional Share") will include the holding period of the shares of IXYS common stock surrendered. If a holder acquired different blocks of shares of IXYS common stock at different times or different prices, such holder should consult his, her or its tax advisor as to the determination of the tax bases and holding periods of the stock consideration received in the initial merger.

        Holders electing to receive the all-stock consideration in the initial merger may be subject to proration (see the section titled "The Merger—Merger Consideration"), which may result in the receipt of a portion of the merger consideration in cash consideration, in addition to the stock consideration. See the section titled "—Exchange for Littelfuse Common Stock and Cash" for a general description of the U.S. federal income tax consequences to holders of the receipt of stock consideration and cash consideration.

Exchange for Littelfuse Common Stock and Cash

        A holder who receives a combination of stock consideration and cash consideration (other than cash in lieu of a fractional share of Littelfuse common stock) pursuant to the initial merger generally will recognize gain (but not loss) in an amount equal to the lesser of (1) the sum of the amount of cash consideration (other than cash in lieu of a fractional share of Littelfuse common stock) and the fair market value of the stock consideration, minus that holder's adjusted tax basis in its shares of IXYS common stock surrendered in exchange therefor and (2) the amount of cash consideration received.

        If a holder acquired different blocks of shares of IXYS common stock at different times or different prices, any gain or loss may be determined separately for each identifiable block of shares. Holders should consult their tax advisors regarding the manner in which cash consideration and stock consideration should be allocated among different blocks of shares of IXYS common stock surrendered and the determination of the tax bases and holding periods of the stock consideration received.

        Any recognized gain will generally be long-term capital gain if the holder's holding period with respect to the shares of IXYS common stock surrendered is more than one year. In some cases, if a holder actually or constructively owns Littelfuse common stock after the merger, the recognized gain could be treated as having the effect of the distribution of a dividend under the tests set forth in Section 302 of the Code, in which case such holder may have dividend income up to the amount of the cash consideration received. Because the possibility of dividend treatment depends primarily upon the particular circumstances of a holder, including the application of certain constructive ownership rules, holders should consult their tax advisors regarding the potential tax consequences of the merger to them, and holders that are corporations should consult their tax advisors regarding the potential applicability of the "extraordinary dividend" provisions of the Code.

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        The aggregate tax basis of the stock consideration received (including fractional shares deemed received and redeemed as described in the section titled "—Cash in Lieu of a Fractional Share") will be equal to the aggregate adjusted tax basis of the shares of IXYS common stock surrendered, reduced by the amount of cash consideration received by the holder (excluding any cash in lieu of a fractional share) and increased by the amount of gain (excluding any gain recognized with respect to cash in lieu of a fractional share), if any, recognized by the holder on the exchange. The holding period of the stock consideration (including fractional shares deemed received and redeemed as described below) will include the holding period of the shares of IXYS common stock surrendered.

        Holders receiving a combination of stock consideration and cash consideration should consult their tax advisors regarding the manner in which the above rules would apply in the holder's particular circumstances.

Cash in Lieu of a Fractional Share

        A holder who receives cash in lieu of a fractional share of Littelfuse common stock will generally be treated as having received such fractional share and then as having received such cash in redemption of the fractional share. Gain or loss generally will be recognized based on the difference between the amount of cash in lieu of the fractional share and the tax basis allocated to such fractional share. Such gain or loss generally will be long-term capital gain or loss if the holding period for such shares is more than one year. In some cases, if a holder actually or constructively owns Littelfuse common stock after the merger, the recognized gain could be treated as having the effect of the distribution of a dividend under the tests set forth in Section 302 of the Code, in which case such holder may have dividend income up to the amount of the cash consideration received. Because the possibility of dividend treatment depends primarily upon the particular circumstances of a holder, including the application of certain constructive ownership rules, holders should consult their tax advisors regarding the potential tax consequences of the merger to them, and holders that are corporations should consult their tax advisors regarding the potential applicability of the "extraordinary dividend" provisions of the Code.

Information Reporting and Backup Withholding

        Information reporting and backup withholding may apply to payments made in connection with the initial merger. Backup withholding will not apply, however, if the recipient provides proof of an applicable exemption or furnishes its taxpayer identification number and otherwise complies with all applicable certification requirements. Any amounts withheld may be allowed as a refund or credit against such holder's U.S. federal income tax liability provided the required information is timely furnished to the IRS.

        This summary of the material U.S. federal income tax consequences of the merger is for general information only and is not tax advice. Holders of IXYS common stock should consult their tax advisors as to the specific tax consequences to them of the merger in light of their particular circumstances, including the applicability and effect of any U.S. federal, state, local, foreign and other tax laws.

Regulatory Approvals

        Littelfuse, IXYS and Merger Sub have each agreed to use their respective reasonable best efforts to take, or cause to be taken, all reasonable actions, and to do, or cause to be done, all reasonable things necessary, proper or advisable under any applicable laws to consummate the merger and obtain (and to cooperate with each other in obtaining) the required regulatory approvals. The following is a summary of the material regulatory approvals required for completion of the transactions contemplated by the merger agreement. There can be no assurance, however, if and when any of the approvals

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required to be obtained for the transactions contemplated by the merger agreement will be obtained or as to the conditions or limitations that such approvals may contain or impose.

United States Antitrust Clearance

        Under the HSR Act, and related rules, the merger may not be completed until each party files a Notification and Report Form with the Antitrust Division and the FTC and all statutory waiting period requirements have been satisfied. A transaction requiring notification under the HSR Act may not be completed until the expiration of a 30-calendar-day waiting period following the parties' filing of their respective HSR Act Notification and Report Forms or the early termination of that waiting period. On September 18, 2017, Littelfuse and IXYS filed their respective Notification and Report Forms and on October 2, 2017, the parties received early termination of the HSR waiting period.

        U.S. state attorneys general could take action under the antitrust laws as they deem necessary or desirable in the public interest including without limitation seeking to enjoin the completion of the merger or permitting completion subject to the divestiture of assets of Littelfuse or IXYS or other remedies. Private parties may also seek to take legal action under the antitrust laws under some circumstances. There can be no assurance that a challenge to the merger on antitrust grounds will not be made or, if such challenge is made, that it would not be successful.

German Antitrust Clearance

        Under the merger agreement, the parties' obligations to complete the merger are also conditioned on the receipt of approvals, consents or clearances required in connection with the transactions contemplated by the merger agreement under the antitrust/merger control laws of Germany. On September 25, 2017, Littelfuse and IXYS filed a notification to satisfy the filing requirements in connection with obtaining the clearances and approvals applicable to the merger under the antitrust/merger control laws of Germany, and on October 6, 2017, the parties received the required clearance.

Other Regulatory Approvals

        In addition to the regulatory approvals described above, the merger may require the approval of other governmental authorities under foreign regulatory laws, such as under foreign merger control laws. If it is determined that other filings are required or advisable, it is possible that any of the governmental entities with which filings are made may seek, as conditions for granting approval of the merger, various regulatory concessions. Neither Littelfuse nor IXYS is currently aware of any material governmental approvals or actions that are required for completion of the merger other than those described above. It is currently contemplated that if any such additional material governmental approvals or actions are required, those approvals or actions will be sought.

        Under the merger agreement, Littelfuse, IXYS and Merger Sub have each agreed to use their respective reasonable best efforts to consummate the merger and obtain the regulatory approvals described above.

        For additional information, please see the section titled "Risk Factors—Risks Relating to the Merger" beginning on page 31.

Exchange of Shares; Elections As to Form of Consideration

        At the effective time of the initial merger, each issued and outstanding share of IXYS common stock (other than (i) cancelled shares or (ii) dissenting shares) will be converted into the right to receive, at the election of the stockholder and subject to proration, $23.00 in cash, less any applicable withholding taxes and without interest, or 0.1265 of a share of Littelfuse common stock. No fractional

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shares of Littelfuse common stock will be issued in the merger, and holders of IXYS common stock will instead receive cash in lieu of fractional shares of Littelfuse common stock.

        Prior to the effective time of the initial merger, Littelfuse will appoint an exchange agent reasonably acceptable to IXYS with respect to the exchange of shares of IXYS common stock for the merger consideration. At or prior to the effective time, Littelfuse will deposit (i) cash sufficient to pay the aggregate cash portion of the merger consideration and, to the extent determinable, cash in lieu of fractional shares and (ii) evidence of Littelfuse common stock in book-entry or certificated form representing the number of shares of Littelfuse common stock sufficient to deliver the aggregate stock portion of the merger consideration.

        As described above, IXYS stockholders will not receive any fractional shares of Littelfuse common stock in the merger. Instead, a stockholder of IXYS who otherwise would have received a fractional share of Littelfuse common stock will be entitled to receive, from the exchange agent appointed by Littelfuse pursuant to the merger agreement, a cash payment in lieu of such fractional share in an amount determined by multiplying (i) the volume weighted average price per share (calculated to the nearest one-hundredth of one cent) of Littelfuse common stock on The NASDAQ Global Select Market, for the consecutive period of ten trading days beginning on the opening of trading on the twelfth trading day immediately preceding the effective time and concluding at the close of trading on the third trading day immediately preceding the effective time, as calculated by Bloomberg Financial LP under the function "VWAP" by (ii) the fraction of a share (after taking into account all shares of IXYS common stock held by such holder at the effective time and rounded to the nearest one thousandth when expressed in decimal form) of Littelfuse common stock to which such holder would otherwise be entitled, less any applicable withholding taxes.

        If a dividend or other distribution is declared with respect to shares of Littelfuse common stock with a record date after the effective time of the initial merger, such declaration will include a dividend or other distribution in respect of all shares of Littelfuse common stock issuable pursuant to the merger agreement.

        The merger agreement provides that IXYS stockholders will be provided with a form of election and other customary transmittal materials. The form of election will allow each holder of IXYS common stock to specify (i) the number of shares of IXYS common stock owned by such holder with respect to which such holder desires to receive the cash consideration and (ii) the number of shares of IXYS common stock owned by such holder with respect to which such holder desires to receive the stock consideration.

        Littelfuse will initially make available and mail the form of election at least 20 business days prior to the anticipated election deadline to holders of record as of the business day prior to such mailing date. Following the mailing date, Littelfuse will use all reasonable efforts to make available as promptly as possible a form of election to any stockholder who requests a form of election prior to the election deadline, regardless of whether the stockholder was a holder of record as of the business day prior to such mailing date. The election deadline will be 5:00 p.m. local time (in the city in which the principal office of the exchange agent is located) on the date which Littelfuse and IXYS agree is as near as practicable to two business days before the closing date of the transaction. IXYS and Littelfuse will cooperate to issue a press release reasonably satisfactory to each of them announcing the election deadline not more than 15 business days before, and at least five business days prior to, the election deadline.

        To make a valid election, an IXYS stockholder must submit to the exchange agent a properly completed and signed form of election (including duly executed transmittal materials included in the form of election). The form of election must also be accompanied by any certificates representing all certificated shares of IXYS common stock to which such form of election relates (or by an appropriate customary guarantee of delivery of such certificates, as set forth in such form of election, from a

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member of any registered national securities exchange or a commercial bank or trust company in the United States).

        An IXYS stockholder may, at any time prior to the election deadline, change or revoke an election by written notice to the exchange agent received by the exchange agent prior to the election deadline accompanied by a properly completed and signed revised form of election, or by withdrawing his or her shares of IXYS common stock previously deposited with the exchange agent. If any election is not properly made with respect to any shares of IXYS common stock, such election will be deemed to be not in effect, and the shares of IXYS common stock covered by such election will be deemed to be non-election shares, unless a proper election is subsequently timely made.

        After the effective time of the initial merger, shares of IXYS common stock will no longer be outstanding, will be cancelled and will cease to exist and each certificate or book entry share that previously represented shares of IXYS common stock (other than (i) cancelled shares or (ii) dissenting shares) will represent only the right to receive the merger consideration pursuant to the merger agreement, cash in lieu of fractional shares and unpaid dividends and distributions, if any, as described above. With respect to such shares of Littelfuse common stock deliverable upon the surrender of IXYS stock certificates or book-entry shares, until holders of such IXYS stock certificates or book-entry shares have properly surrendered such stock certificates or book-entry shares to the exchange agent for exchange, along with a duly completed letter of transmittal and any other documents as may customarily be required by the exchange agent, those holders will not receive the merger consideration, any cash in lieu of fractional shares and any dividends or distributions that become due to the holders of converted IXYS common stock.

        Within five business days after the effective time, the exchange agent will mail to each record holder of shares of IXYS common stock whose shares of IXYS common stock were converted in the initial merger into the right to receive the merger consideration, and who has not previously submitted an election notice with duly executed transmittal materials, a letter of transmittal and instructions for surrendering IXYS share certificates or book-entry shares in exchange for the merger consideration. Upon surrender of IXYS share certificates or book-entry shares and a duly executed letter of transmittal to the exchange agent in compliance with the instructions for surrender, Littelfuse will, in exchange for such certificates or book-entry shares, cause the exchange agent to pay and deliver the merger consideration and any fractional share cash amounts.

        Littelfuse will instruct the exchange agent to pay the merger consideration and any fractional share cash amounts within five business days following the later to occur of (i) the effective time and (ii) the exchange agent's receipt of the share certificate or book-entry share. The time that any individual stockholder receives its, his or her merger consideration will vary depending on the underlying arrangements through which such stockholder holds its, his or her shares of IXYS common stock.

Dividend Policy

        Littelfuse currently pays regular quarterly cash dividends on its common stock. Littelfuse most recently paid a cash dividend on September 7, 2017, of $0.37 per share. Littelfuse currently expects to continue to pay quarterly cash dividends, although they remain subject to determination and declaration by Littelfuse's board of directors. The payment of future dividends, if any, will be based on several factors, including Littelfuse's financial performance, outlook and liquidity.

        IXYS pays quarterly cash dividends on its common stock at the discretion of its board of directors. IXYS most recently paid a cash dividend on July 5, 2016 of $0.04 per share. The payment of future dividends, if any, will be based on IXYS' financial performance.

        Under the terms of the merger agreement, during the period before the closing of the merger, Littelfuse is not permitted to pay any dividends or make any distributions on its capital stock other

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