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The information in this preliminary proxy statement/prospectus/information statement is not complete and may be changed. The registrant may not sell the securities described in this preliminary proxy statement/prospectus/information statement until the registration statement filed with the Securities and Exchange Commission is declared effective. This preliminary proxy statement/prospectus/information statement is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

Exhibit 99.1

PRELIMINARY — SUBJECT TO COMPLETION, DATED SEPTEMBER 27, 2022

AVISTA PUBLIC ACQUISITION CORP. II

A Cayman Islands Exempted Company
(Company Number 306402)
65 East 55th Street, 18th Floor
New York, NY 10022

PROXY STATEMENT FOR
EXTRAORDINARY GENERAL MEETING OF
AVISTA PUBLIC ACQUISITION CORP. II
(A CAYMAN ISLANDS EXEMPTED COMPANY)

PROSPECTUS FOR
149,137,552 SHARES OF COMMON STOCK AND
7,666,667 REDEEMABLE WARRANTS
OF
AVISTA PUBLIC ACQUISITION CORP. II
(AFTER ITS DOMESTICATION AS A CORPORATION INCORPORATED IN THE STATE
OF DELAWARE), THE CONTINUING ENTITY FOLLOWING THE DOMESTICATION, WHICH WILL BE RENAMED “OMNIAB, INC.” IN CONNECTION WITH
THE BUSINESS COMBINATION DESCRIBED HEREIN

Dear Avista Public Acquisition Corp. II Shareholders:

You are cordially invited to attend an extraordinary general meeting (the “extraordinary general meeting”) of Avista Public Acquisition Corp. II., a Cayman Islands exempted company (“APAC”), at the offices of Weil, Gotshal & Manges LLP, located at 767 Fifth Avenue, New York, NY 10153, at 10:00 a.m., Eastern Time, on [•], 2022, or at such other time and place to which the meeting may be adjourned. Rather than attending in person, we encourage you to attend via live webcast at https://www.cstproxy.com/avistapac/2022.

At the extraordinary general meeting, APAC shareholders will be asked to consider and vote upon a proposal, which is called the “Business Combination Proposal” and described in further detail below, to approve the business combination between APAC and OmniAb, Inc. (“OmniAb”), a Delaware corporation that will own and operate the antibody discovery business of Ligand Pharmaceuticals Incorporated, a Delaware corporation and currently the parent company of OmniAb (“Ligand”). The business combination will be effected by the transaction steps set forth in the Agreement and Plan of Merger, dated as of March 23, 2022 (as the same may be amended, the “Merger Agreement”), by and among Ligand, OmniAb, APAC, and Orwell Merger Sub Inc., a Delaware corporation and wholly-owned subsidiary of APAC (“Merger Sub”), and the related transaction documents named therein. The business combination is being accomplished through what is commonly referred to as a “Reverse Morris Trust” transaction.

As further described in the accompanying proxy statement/prospectus/information statement, the business combination of APAC and OmniAb contemplated by the Merger Agreement (the “Business Combination”) will be accomplished by way of the following transaction steps:

•

APAC’s jurisdiction of incorporation will be changed by its deregistering as an exempted company in the Cayman Islands and continuing and domesticating as a corporation incorporated under the laws of the State of Delaware at least one (1) business day prior to the consummation of the Merger (as defined below) (the “Domestication”). As more fully described elsewhere in the accompanying proxy statement/prospectus/information statement, you will be asked to consider and vote upon a proposal to approve the Domestication (the “Domestication Proposal”). In connection with the consummation of the Domestication, APAC will change its name to “OmniAb, Inc.” (APAC, following the Domestication, is sometimes referred to in the proxy statement/prospectus/information statement as “New OmniAb”);

•

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$0.0001 per share, of New OmniAb (the “New OmniAb Common Stock”), (2) each then issued and outstanding Class B ordinary share, par value $0.0001 per share, of APAC (the “APAC Class B Ordinary Shares”) will convert automatically, on a one-for-one basis, into a share of New OmniAb Common Stock, (3) each then issued and outstanding warrant of APAC (the “APAC Warrants”) will convert automatically into a warrant to acquire one share of New OmniAb Common Stock (the “New OmniAb Warrants”) pursuant to the Warrant Agreement, dated August 9, 2021 (the “Warrant Agreement”), by and between APAC and Continental Stock Transfer & Trust Company (“Continental”), a New York corporation, as warrant agent, and (4) each then issued and outstanding unit of APAC (the “APAC Units”), will separate and convert automatically into one share of New OmniAb Common Stock and one-third of one New OmniAb Warrant. As used in the accompanying proxy statement/prospectus/information statement, “public shares” shall mean the APAC Class A Ordinary Shares (including those that underlie the APAC Units) that were issued pursuant to APAC’s initial public offering and the shares of New OmniAb Common Stock issued as a matter of law upon the conversion thereof on the effective date of the Domestication, as applicable. For further details, see “Shareholder Proposal No. 2 — The Domestication Proposal” in the accompanying proxy statement/prospectus/information statement;

•

Pursuant to a Separation and Distribution Agreement, dated as of March 23, 2022, by and among Ligand, OmniAb and APAC (the “Separation Agreement”), Ligand will, among other things and subject to the terms and conditions of the Separation Agreement, transfer the OmniAb Business (as defined below), including certain related subsidiaries of Ligand, to OmniAb (the “Separation”) and make a contribution to the capital of OmniAb of $15,000,000, less certain transaction and other expenses;

•

Following the Separation and on the day of the Merger described below, Ligand will distribute (the “Distribution”) to Ligand stockholders 100% of the common stock of OmniAb, par value $0.001 per share (the “OmniAb Common Stock”) on a pro rata basis;

•

Pursuant to the Employee Matters Agreement, dated March 23, 2022, as amended by that certain Amended and Restated Employee Matters Agreement, dated as of August 18, 2022, (the “Employee Matters Agreement”), by and among Ligand, OmniAb, APAC and Merger Sub, at the time of the Distribution, (i) each existing Ligand equity award granted prior to March 2, 2022, with certain limited exceptions, will be split into (A) a new Ligand equity award (B) a new OmniAb Equity Award, with any in-the-money value in the original Ligand equity award split between such awards based on the relative values of Ligand and OmniAb at the time of the Distribution, and (ii) each existing Ligand equity award granted on or after March 2, 2022 will be converted into either (A) if the holder will be a Ligand service provider following the Distribution, an adjusted Ligand equity award, or (B) if the holder will be an OmniAb service provider following the Distribution, a New OmniAb Equity Award, with the intrinsic value of such adjusted or converted award equal to the intrinsic value in the original Ligand equity award based on the relative values of Ligand and OmniAb at the time of the Distribution;

•

Pursuant to the Amended and Restated Forward Purchase Agreement, dated March 23, 2022 (the “A&R FPA”), by and among APAC, Avista Acquisition LP II (the “Sponsor”) and OmniAb, New OmniAb will issue and sell to the Sponsor 1,500,000 shares of New OmniAb Common Stock and warrants to acquire 1,666,667 shares of New OmniAb Common Stock for an aggregate purchase price of $15,000,000, with such purchase to be consummated following the Domestication and prior to the Merger (the “Forward Purchase”). In addition, pursuant to the A&R FPA, the Sponsor has agreed to purchase up to an additional 10,000,000 shares of New OmniAb Common Stock (the “Redemption Backstop”) and up to an additional 1,666,667 New OmniAb Warrants, for an aggregate additional purchase price of up to $100,000,000, in order to backstop shareholder redemptions to the extent such redemptions would result in the cash proceeds available to the combined company following the Business Combination from APAC’s trust account to be less than $100,000,000; and

•

Following the above steps, Merger Sub will merge with and into OmniAb (the “Merger”), with OmniAb continuing as the surviving company in the Merger and a wholly-owned subsidiary of APAC. As a result of the Merger, the existing shares of OmniAb Common Stock will automatically convert into the right to receive shares of New OmniAb Common Stock in accordance with an exchange ratio described below. In addition, in connection with the consummation of the Merger and prior to the consummation of the Domestication, the surviving company will be renamed “OmniAb Operations, Inc.” (New OmniAb, following the consummation of the Business Combination, is sometimes referred to in the accompanying proxy statement/prospectus/information statement as the “combined company”).

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In addition to the Business Combination Proposal and the Domestication Proposal, you will also be asked to consider and vote upon (1) a proposal to approve and adopt the proposed certificate of incorporation and bylaws of New OmniAb in connection with the Domestication (the “Organizational Documents Proposal”), (2) proposals to approve, on a non-binding advisory basis, certain material differences between APAC’s Amended and Restated Memorandum and Articles of Association (as it may be amended from time to time, the “Cayman Constitutional Documents”) and the proposed certificate of incorporation and bylaws of New OmniAb, presented separately in accordance with the United States Securities and Exchange Commission’s requirements (collectively, the “Non-Binding Governance Proposals”), (3) a proposal to approve for the purposes of complying with the applicable provisions of Nasdaq Stock Market Rule 5635, the issuance of shares of New OmniAb Common Stock in connection with the Domestication, the Forward Purchase, the Redemption Backstop and the Merger (the “Stock Issuance Proposal”), (4) a proposal to approve the adoption by New OmniAb of the OmniAb, Inc. 2022 Incentive Award Plan (the “Incentive Plan Proposal”), (5) a proposal to approve the adoption by New OmniAb of the OmniAb, Inc. 2022 Employee Stock Purchase Plan (the “ESPP Proposal”), (6) a proposal to elect seven directors to the New OmniAb board of directors (the “New OmniAb Board”) effective as of the closing of the Business Combination (the “Closing”) (the “Director Election Proposal”), and (7) a proposal to approve the adjournment of the extraordinary general meeting to a later date or dates, if necessary, to permit further solicitation of proxies in the event that there are not sufficient votes to constitute a quorum or approve and adopt any one or more of the foregoing proposals at the extraordinary general meeting (the “Adjournment Proposal”).

The transactions contemplated by the Merger Agreement will be consummated only if the Business Combination Proposal, the Domestication Proposal, the Organizational Documents Proposal, the Stock Issuance Proposal, the Incentive Plan Proposal, the ESPP Proposal, and the Director Election Proposal (collectively the “Condition Precedent Proposals”) are approved at the extraordinary general meeting. Each of the Condition Precedent Proposals is cross-conditioned on the approval of the others. Each of these proposals is more fully described in the accompanying proxy statement/prospectus/information statement, which each shareholder is encouraged to read carefully and in its entirety.

The total number of shares of New OmniAb Common Stock to be received by OmniAb’s stockholders (as of immediately after consummation of the Distribution) or reserved for issuance pursuant to the New OmniAb Equity Awards into which OmniAb Equity Awards are converted (other than the OmniAb Earnout Shares (as defined below) and other than out-of-the-money OmniAb Options (each, an “Out-of-the-Money OmniAb Option”) will be equal to the quotient obtained by dividing (x) the sum of (i) $850,000,000, plus (ii) the aggregate exercise price of all in-the-money options to purchase OmniAb Common Stock that are outstanding immediately prior to the effective time of the Merger (the “Effective Time”), as determined on an aggregate basis (each, an “In-the-Money OmniAb Option”), by (y) $10.00 (the “Aggregate Merger Consideration”). In addition to the Aggregate Merger Consideration, holders of OmniAb Common Stock and New OmniAb Equity Awards will also receive at the Closing earnout consideration in the form of an additional 15,000,000 shares of New OmniAb Common Stock (the “OmniAb Earnout Shares”), with 50% of such earnout shares vesting upon the achievement of a post-transaction volume-weighted average price (“VWAP”) of $12.50 per share of New OmniAb Common Stock for any 20 trading days over a consecutive 30 trading-day period, and the remainder vesting upon achievement of a post-transaction VWAP of $15.00 per share of New OmniAb Common Stock for any 20 trading days over a consecutive 30 trading-day period, in each case provided such vesting occurs during the five-year period following the Closing; provided, that in the event of a Change of Control (as defined in the Merger Agreement) between the date of the Closing to and including the fifth anniversary of the date of the Closing pursuant to which New OmniAb or any of its stockholders have the right to receive, directly or indirectly, cash, securities or other property attributing a value of at least $12.50 (with respect to 50% of the OmniAb Earnout Shares) or $15.00 (with respect to all OmniAb Earnout Shares) per share of New OmniAb Common Stock, and such Change of Control has been approved by a majority of the independent directors of the New OmniAb Board, then such OmniAb Earnout Shares shall be deemed to have vested immediately prior to such Change of Control.

As a result of and upon the Closing, among other things, each outstanding share of OmniAb Common Stock (other than Treasury Shares (as defined below)), will be cancelled upon the Effective Time in exchange for the right to receive (i) a number of shares of New OmniAb Common Stock equal to the quotient obtained by dividing (x) the Aggregate Merger Consideration by (y) the aggregate number of shares of OmniAb Common Stock that are outstanding on a fully diluted basis as of immediately prior to the Effective Time (excluding any shares underlying options to purchase OmniAb Common Stock other than In-the-Money OmniAb Options), determined in accordance with the terms of the Merger Agreement (the “Base Exchange Ratio”), and (ii) a number of OmniAb Earnout Shares equal to the quotient obtained by dividing

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(x) 15,000,000 by (y) the aggregate number of shares of OmniAb Common Stock that are outstanding on a fully diluted basis as of immediately prior to the Effective Time, determined in accordance with the terms of the Merger Agreement (the “Earnout Exchange Ratio”).

In addition, all (i) options to purchase shares of OmniAb Common Stock (each, an “OmniAb Option”), (ii) restricted stock units relating to OmniAb Common Stock (each, an “OmniAb RSU”) and (iii) performance-vesting restricted stock units relating to OmniAb Common Stock (each, an “OmniAb PSU,” and together with the OmniAb Options and the OmniAb RSUs, the “OmniAb Equity Awards”), in each case, that are outstanding as of immediately prior to the Effective Time, will be converted into such number of (a) options to purchase shares of New OmniAb Common Stock (each, a “New OmniAb Option”), (b) restricted stock units relating to shares of New OmniAb Common Stock (each, a “New OmniAb RSU”) and (c) performance-vesting restricted stock units relating to shares of New OmniAb Common Stock (each, a “New OmniAb PSU”), respectively, in each case, equal to (1) the number of shares of OmniAb Common Stock underlying such OmniAb Equity Awards immediately prior to the Effective Time multiplied by (2) the Base Exchange Ratio. Each holder of an OmniAb Option, OmniAb RSU and/or OmniAb PSU will also receive a number of OmniAb Earnout Shares equal to the number of shares of OmniAb Common Stock underlying such OmniAb Options, OmniAb RSUs and/or OmniAb PSUs, as applicable, multiplied by the Earnout Exchange Ratio, and the exercise price of each outstanding New OmniAb Option will be equal to the exercise price of the pre-conversion OmniAb Option divided by the Base Exchange Ratio.

The calculation of the total number of shares of New OmniAb Common Stock to be received by OmniAb’s (Ligand’s) stockholders in the Business Combination, the Base Exchange Ratio and the Earnout Exchange Ratio will be based on the number of outstanding OmniAb Equity Awards (OmniAb Options, OmniAb RSUs and OmniAb PSUs) following the Distribution, including the exercise prices of the OmniAb Options, and the number of shares of Ligand Common Stock outstanding as of the Ligand Record Date for the Distribution. The calculation of the number and exercise prices of the OmniAb Equity Awards will be based on the relative trading values of the Ligand Common Stock in the “regular way” and “ex-distribution” markets during the five-trading-day period prior to the Closing. As such, the total number of shares of New OmniAb Common Stock to be received by OmniAb’s (Ligand’s) stockholders and the Base Exchange Ratio and Earnout Exchange Ratio are not determinable until the Closing. However, for illustrative purposes, based on an assumed trading price of Ligand Common Stock of $89.22 per share (the closing price of the Ligand Common Stock on June 30, 2022) and the number of shares of Ligand Common Stock and equity awards outstanding as of June 30, 2022, and an assumed trading price of Ligand Common Stock in the “regular way” and “ex-distribution” trading markets of $89.22 and $40.20 per share, respectively, there would be an aggregate of 97,731,592 shares of New OmniAb Common Stock (inclusive of the Earnout Shares) received by OmniAb’s (Ligand’s) stockholders in the Business Combination; there would be 13,587,254 OmniAb Options and an aggregate of 1,402,039 OmniAb RSUs and OmniAb PSUs outstanding following the Distribution and the Base Exchange Ratio and the Earnout Exchange Ratio would be approximately 4.9 and 0.75, respectively. As discussed above, the exact number of shares to be received by OmniAb’s (Ligand’s) stockholders and related exchange ratios will not be calculable until the Closing, and the trading price of Ligand Common Stock in the “regular way” and “ex-distribution” markets may fluctuate and be materially different than this illustrative example. See “Questions and Answers” on pages 20-21 in the accompanying proxy statement/prospectus/information statement for a description of these markets for Ligand Common Stock.

It is anticipated that, following the Business Combination, (1) APAC’s public shareholders are expected to own approximately 18.0% (assuming no public shareholders exercise their redemption rights in connection with the Business Combination (the “no redemption scenario”)) or 0% (assuming that 23,000,000 APAC Class A Ordinary Shares are redeemed in connection with the Business Combination and the Sponsor funds $100,000,000 pursuant to the Redemption Backstop provided for in the A&R Forward Purchase Agreement (the “maximum redemption scenario”)) of the outstanding shares of New OmniAb Common Stock, (2) OmniAb stockholders (without taking into account any public shares held by Ligand stockholders prior to the consummation of the Business Combination) are expected to own approximately 76.3% (assuming the no redemption scenario) or 85.0% (assuming the maximum redemption scenario) of the outstanding shares of New OmniAb Common Stock and (3) the Sponsor and related parties are expected to collectively own approximately 5.7% (assuming the no redemption scenario) or 15.0% (assuming the maximum redemption scenario) of the outstanding shares of New OmniAb Common Stock. These percentages (i) assume that (a) New OmniAb issues 97,731,592 shares of New OmniAb Common Stock to former stockholders of OmniAb and former holders of OmniAb Equity Awards as of immediately prior to the Effective Time (based on the illustrative calculations discussed in the preceding paragraph), (b) that New OmniAb issues 1,500,000 shares of New OmniAb Common Stock to the Sponsor pursuant to the Forward

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Purchase and (c) solely in the case of the maximum redemption scenario, that New OmniAb issues an additional 10,000,000 shares of New OmniAb Common Stock to the Sponsor pursuant to the Redemption Backstop, (ii) exclude all New OmniAb Options that may be exercisable for shares of New OmniAb Common Stock, New OmniAb RSUs and New OmniAb PSUs, (iii) include the Sponsor Earnout Shares and the OmniAb Earnout Shares and (iv) exclude the impact of any New OmniAb Warrants that will be outstanding following the Business Combination. If the actual facts are different from the no redemption scenario or maximum redemption scenario, the percentage ownership of New OmniAb held by such constituencies will be different.

In connection with the Business Combination, certain related agreements have been, or will be, entered into on or prior to the date of the Closing, including (i) the Separation Agreement, (ii) the A&R Registration Rights Agreement (as defined below), (iii) the Tax Matters Agreement (as defined below), (iv) the Employee Matters Agreement, (v) the Transition Services Agreements (as defined below), (vi) the A&R FPA, and (vii) the Sponsor Insider Agreement (as defined below). The A&R Registration Rights Agreement will also provide that the Sponsor’s right to designate individuals to be appointed or nominated for election to the APAC Board will be reduced from three (3) individuals to one (1) individual, and that such right will only exist until the later of (i) such time as the Sponsor ceases to beneficially own at least 10% of APAC’s outstanding voting stock and (ii) subject to compliance with the rules of Nasdaq, the third anniversary of the date of the Merger Agreement. Moreover, any individual nominated by the Sponsor will require the consent of the New OmniAb Board, subject to certain exceptions. For additional information, see “Shareholder Proposal No. 1 — The Business Combination Proposal — Summary of the Separation Agreement” and “— Summary of the Ancillary Agreements” in the accompanying proxy statement/prospectus/information statement.

Pursuant to the Cayman Constitutional Documents, any holder of public shares (a “public shareholder”), excluding shares held by the Sponsor and certain related parties, may request that APAC redeem all or a portion of such shareholder’s public shares for cash if the Business Combination is consummated. Holders of APAC Units must elect to separate the units into the underlying public shares and warrants prior to exercising redemption rights with respect to the public shares. If holders hold their APAC Units in an account at a brokerage firm or bank, holders must notify their broker or bank that they elect to separate the units into the underlying public shares and warrants, or if a holder holds APAC Units registered in its own name, the holder must contact Continental, APAC’s transfer agent, directly and instruct it to do so. Public shareholders may elect to redeem their public shares even if they vote “for” the Business Combination Proposal or any other Condition Precedent Proposal. If the Business Combination is not consummated, the public shares will be returned to the respective holder, broker or bank. If the Business Combination is consummated, and if a public shareholder properly exercises its right to redeem all or a portion of the public shares that it holds and timely delivers its shares to Continental, APAC will redeem such public shares for a per-share price, payable in cash, equal to the pro rata portion of the trust account established at the consummation of our initial public offering (the “trust account”), calculated as of two business days prior to the consummation of the Business Combination. For illustrative purposes, as of [•], 2022, this would have amounted to approximately $[•] per issued and outstanding public share. If a public shareholder exercises its redemption rights in full, then it will be electing to exchange its public shares for cash and will no longer own public shares. The redemption takes place following the Domestication and, accordingly, it is shares of New OmniAb Common Stock that will be redeemed immediately after consummation of the Business Combination. See “Extraordinary General Meeting of APAC — Redemption Rights” in the accompanying proxy statement/prospectus/information statement for a detailed description of the procedures to be followed if you wish to redeem your public shares for cash.

Notwithstanding the foregoing, a public shareholder, together with any affiliate of such public shareholder or any other person with whom such public shareholder is acting in concert or as a “group” (as defined in Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”)), will be restricted from redeeming its public shares with respect to more than an aggregate of 15% of the public shares. Accordingly, if a public shareholder, alone or acting in concert or as a group, seeks to redeem more than 15% of the public shares, then any such shares in excess of that 15% limit would not be redeemed for cash.

The Sponsor and each director of APAC have agreed to, among other things, vote in favor of the Merger Agreement and the transactions contemplated thereby, including the Condition Precedent Proposals, and to waive their redemption rights in connection with the consummation of the Business Combination with respect to any ordinary shares held by them. Such persons agreed to waive their redemption rights in order to induce APAC and APAC’s underwriter to enter into the underwriting agreement executed and

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delivered in connection with the initial public offering. The Class B Ordinary Shares held by the Sponsor and such other persons will be excluded from the pro rata calculation used to determine the per-share redemption price. As of the date of the accompanying proxy statement/prospectus/information statement, the Sponsor and APAC’s directors, collectively, own 20% of the issued and outstanding ordinary shares of APAC.

The Merger Agreement provides that the obligations of the parties to consummate the Merger are conditioned on, among other things, (i) the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, (ii) receipt of required consents and approvals from certain governmental authorities, (iii) no agreement between Ligand or APAC and any governmental authority pursuant to which Ligand or APAC has agreed not to consummate the Business Combination shall be in effect, (iv) no governmental authority of competent jurisdiction shall have enacted, issued or granted any law (whether temporary, preliminary or permanent), in each case that is in effect and which has the effect of restraining, enjoining or prohibiting the consummation of the transaction, (v) APAC shall have at least $5,000,001 of net tangible assets as of the Closing, (vi) the New OmniAb Common Stock issuable pursuant to the Business Combination shall have been approved for listing on Nasdaq, subject to official notice of issuance, (vii) Ligand, OmniAb, APAC and Merger Sub shall each have performed and complied in all material respects with the obligations, covenants and agreements required by the Merger Agreement to be performed or complied with by it at or prior to the Effective Time, (viii) customary bring down conditions related to the accuracy of the parties’ respective representations and warranties in the Merger Agreement, (ix) the consummation of the Separation, the Distribution and the other transactions contemplated by the Separation Agreement, (x) each of APAC’s and OmniAb’s registration statements to be filed with the United States Securities and Exchange Commission shall have become effective, (xi) APAC’s shareholder approval of the Condition Precedent Proposals shall have been obtained and (xii) the receipt by Ligand and APAC of certain tax opinions. In addition, the respective obligations of OmniAb and Ligand to consummate the Business Combination are conditioned upon, among other items, the completion of the Forward Purchase and the Redemption Backstop, the resignation of all directors and all executive officers of APAC and the occurrence of the Domestication. APAC’s obligation to consummate the Business Combination is also conditioned on there having been no “Material Adverse Effect” on OmniAb since the date of the Merger Agreement that is continuing.

The Merger Agreement is also subject to the satisfaction or waiver of certain other closing conditions as described in the accompanying proxy statement/prospectus/information statement. There can be no assurance that the parties to the Merger Agreement would waive any such provision of the Merger Agreement if it is not satisfied as of the time of satisfaction of all other conditions precedent to the Merger.

APAC is providing the accompanying proxy statement/prospectus/information statement and accompanying proxy card to APAC’s shareholders in connection with the solicitation of proxies to be voted at the extraordinary general meeting and at any adjournments of the extraordinary general meeting. Information about the extraordinary general meeting, the Business Combination and other related business to be considered by APAC’s shareholders at the extraordinary general meeting is included in the accompanying proxy statement/prospectus/information statement. Whether or not you plan to attend the extraordinary general meeting, all of APAC’s shareholders are urged to read the accompanying proxy statement/prospectus/information statement, including the Annexes and other documents referred to therein, carefully and in their entirety. You should also carefully consider the risk factors described in “Risk Factors” beginning on page 92 of the accompanying proxy statement/prospectus/information statement.

After careful consideration, the board of directors of APAC (the “APAC Board”) has unanimously approved the Business Combination and unanimously recommends that shareholders vote “FOR” the Business Combination Proposal and the Domestication Proposal and “FOR” all other proposals presented to APAC’s shareholders in the accompanying proxy statement/prospectus/information statement. When you consider the recommendation of these proposals by the APAC Board, you should keep in mind that APAC’s directors and officers have interests in the Business Combination that may conflict with your interests as a shareholder. See the section entitled “Shareholder Proposal No. 1 — The Business Combination Proposal — Interests of APAC’s Directors and Executive Officers in the Business Combination” in the accompanying proxy statement/prospectus/information statement for a further discussion of these considerations.

The approval of the Business Combination Proposal, the Domestication Proposal and the Organizational Documents Proposal each requires a special resolution under Cayman Islands law, being the affirmative vote of the holders of at least two-thirds majority of the APAC ordinary shares represented in person, virtually or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting. The Non-Binding

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Governance Proposals (which are constituted of non-binding advisory proposals), the Director Election Proposal, the Stock Issuance Proposal, the Incentive Plan Proposal, the ESPP Proposal and the Adjournment Proposal each requires an ordinary resolution under Cayman Islands law, being the affirmative vote of the holders of a majority of the ordinary shares represented in person, virtually or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting.

Your vote is very important. Whether or not you plan to attend the extraordinary general meeting, please vote as soon as possible by following the instructions in the accompanying proxy statement/prospectus/information statement to make sure that your shares are represented at the extraordinary general meeting. If you hold your shares in “street name” through a bank, broker or other nominee, you will need to follow the instructions provided to you by your bank, broker or other nominee to ensure that your shares are represented and voted at the extraordinary general meeting. In most cases you may vote by telephone or over the Internet as instructed. The transactions contemplated by the Merger Agreement will be consummated only if the Condition Precedent Proposals are approved at the extraordinary general meeting. Each of the Condition Precedent Proposals is cross-conditioned on the approval of the others. The Adjournment Proposal is not conditioned upon the approval of any other proposal set forth in the accompanying proxy statement/prospectus/information statement. The Non-Binding Governance Proposals are constituted of non-binding advisory proposals.

If you sign, date and return your proxy card without indicating how you wish to vote, your proxy will be voted “FOR” each of the proposals presented at the extraordinary general meeting. If you fail to return your proxy card or fail to instruct your bank, broker or other nominee how to vote, and do not attend the extraordinary general meeting in person, the effect will be, among other things, that your shares will not be counted for purposes of determining whether a quorum is present at the extraordinary general meeting and will not be voted. An abstention will be counted towards the quorum requirement but will not count as a vote cast at the extraordinary general meeting. A broker non-vote, while considered present for the purposes of establishing a quorum, will not count as a vote cast at the extraordinary general meeting. If you are a shareholder of record and you attend the extraordinary general meeting and wish to vote in person, you may withdraw your proxy and vote in person.

If you have any questions or need assistance voting your ordinary shares, please contact D.F. King & Co., Inc., our proxy solicitor, by calling (888) 887-0082, or banks and brokers can call collect at (212) 269-5550 or by emailing AHPA@dfking.com.

TO EXERCISE YOUR REDEMPTION RIGHTS, YOU MUST DEMAND IN WRITING THAT YOUR PUBLIC SHARES ARE REDEEMED FOR A PRO RATA PORTION OF THE FUNDS HELD IN THE TRUST ACCOUNT AND TENDER YOUR SHARES TO APAC’S TRANSFER AGENT AT LEAST TWO BUSINESS DAYS PRIOR TO THE VOTE AT THE GENERAL MEETING. YOU MAY TENDER YOUR SHARES BY EITHER DELIVERING YOUR SHARE CERTIFICATE TO THE TRANSFER AGENT OR BY DELIVERING YOUR SHARES ELECTRONICALLY USING THE DEPOSITORY TRUST COMPANY’S DWAC (DEPOSIT WITHDRAWAL AT CUSTODIAN) SYSTEM. IF THE BUSINESS COMBINATION IS NOT COMPLETED, THEN THESE SHARES WILL BE RETURNED TO YOU OR YOUR ACCOUNT. IF YOU HOLD THE SHARES IN STREET NAME, YOU WILL NEED TO INSTRUCT THE ACCOUNT EXECUTIVE AT YOUR BANK OR BROKER TO WITHDRAW THE SHARES FROM YOUR ACCOUNT IN ORDER TO EXERCISE YOUR REDEMPTION RIGHTS.

On behalf of the APAC Board, we would like to thank you for your support and look forward to the successful completion of the Business Combination.

Sincerely,

Thompson Dean
Chairman of the APAC Board

NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES REGULATORY AGENCY HAS APPROVED OR DISAPPROVED THE TRANSACTIONS DESCRIBED IN THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS/INFORMATION STATEMENT, PASSED UPON THE MERITS OR FAIRNESS OF THE BUSINESS COMBINATION OR RELATED TRANSACTIONS OR PASSED UPON THE ADEQUACY OR ACCURACY OF THE DISCLOSURE IN THE ACCOMPANYING PROXY STATEMENT/

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[ • ], 2022

Dear Ligand Stockholder:

On November 9, 2021, we announced we were pursuing plans to split our company into two separate, publicly traded companies, with one featuring the OmniAb business and the other featuring Ligand’s remaining businesses. We considered multiple ways to pursue a separation with the goals of ensuring a smooth transition of operations, a healthy balance sheet for both OmniAb and Ligand, and support from investors. On February 17, 2022, we announced our intention to accomplish this separation via a distribution to our stockholders of outstanding shares of common stock of OmniAb, Inc. held by Ligand. Subsequently, we received an offer from Avista Public Acquistion Corp. II (“APAC”) to complete a business combination. The APAC team is comprised of high-quality healthcare operators and investors with an excellent track record. They have done extensive due diligence and see the potential and value of OmniAb, a highly competitive, leading platform with strong momentum given recent major clinical and regulatory successes. We are very pleased to partner with APAC and its shareholders to take OmniAb public.

The spin-off of OmniAb through the business combination with APAC is intended to create two companies with dedicated operational focus, business-specific capital allocation, agility to meet partner needs, and compelling focused investment profiles. OmniAb’s business will include the Ab Initio computational antigen design technology, Icagen’s ion channel technology, the xPloration high-throughput screening technology, and the suite of OmniAb transgenic animals used for antibody discovery. Ligand will continue to focus on its existing collection of core royalties and technologies, pipeline and contracts associated with the Pelican protein expression platform and the Captisol business. We believe more than ever that OmniAb offers one of the industry’s leading antibody discovery platforms and that the business is primed for success for years to come. We believe we have been operating two distinct, high-growth companies within Ligand. We are excited to create two independent companies and accelerate investment into the OmniAb platform and technologies to further drive value for our stockholders.

The separation will provide current Ligand stockholders with ownership interests in both Ligand and OmniAb. The principal transactions described in this document include the following:

•

Separation — Ligand and certain of Ligand’s subsidiaries will engage in a series of transactions to transfer OmniAb’s business, including certain related subsidiaries of Ligand, to OmniAb, Inc. and make a contribution to the capital of OmniAb of $15,000,000, less certain transaction and other expenses

•

Distribution — Ligand will distribute to Ligand stockholders 100% of the common stock of OmniAb on a pro rata basis;

•

Merger — Immediately after the distribution, OmniAb will merge with an APAC subsidiary and continue as a wholly owned subsidiary of APAC. As a result of the merger, the existing shares of OmniAb common stock will automatically convert into the right to receive shares of APAC common stock in accordance with an exchange ratio described below.

You do not need to take any action to receive the shares of OmniAb common stock to which you are entitled as a Ligand stockholder. You also do not need to pay any consideration or surrender or exchange any shares of Ligand common stock.

I encourage you to read the proxy statement/prospectus/information statement. The proxy statement/prospectus/information statement describes the separation, the distribution and the merger in detail and contains important business and financial information about OmniAb and APAC as well as the combined company.

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[ • ], 2022

Dear Future OmniAb Stockholder:

We are excited to welcome you as a stockholder of New OmniAb, which will be a separate company after its upcoming spin-off from Ligand and business combination with APAC. We are proud of our accomplishments and growth to date and plan to further expand on our successes moving forward.

The OmniAb discovery platform provides our pharmaceutical industry partners access to diverse antibody repertoires and high-throughput screening technologies to enable discovery of next-generation therapeutics. At the heart of the OmniAb platform is the Biological Intelligence (BI) of our proprietary transgenic animals, including OmniRat, OmniChicken and OmniMouse that have been genetically modified to generate antibodies with human sequences to facilitate development of human therapeutic candidates. OmniFlic (transgenic rat) and OmniClic (transgenic chicken) address industry needs for bispecific antibody applications through a common light chain approach, and OmniTaur features unique structural attributes of cow antibodies for complex targets. We believe the OmniAb animals comprise the most diverse host systems available in the industry and they are optimally leveraged through computational antigen design and immunization methods, paired with high-throughput single B cell screening and deep computational analysis of next-generation sequencing datasets to identify fully human antibodies with superior performance and developability characteristics. An established core competency focused on ion channels and transporters further differentiates our technology and creates opportunities to further leverage across modalities, including antibody-drug conjugates and others. The OmniAb suite of technologies and differentiating computational capabilities and BI features are combined to offer a highly efficient and customizable end-to-end solution for the growing discovery needs of the global pharmaceutical industry.

Our mission is to enable the rapid development of innovative therapeutics by pushing the frontiers of drug discovery technologies. We intend to achieve this mission by enabling the discovery of high-quality therapeutic candidates and by being the partner of choice for pharmaceutical and biotechnology companies. As a standalone company in partnership with the APAC team, we believe we will be well positioned to unleash the full potential of our platform through dedicated operational focus by all members of the new OmniAb team and a capital structure appropriate to our business strategy which will further our ability to meet our partners’ needs.

I personally invite you to learn more about OmniAb by reading the accompanying proxy statement/prospectus/information statement. We have applied to be listed on the Nasdaq Global Market under the symbol “OABI.”

This is an exciting opportunity and the time is right to establish a standalone company. With our heritage and solid foundation derived from Ligand and the capital raised from the merger with APAC, we believe OmniAb is in an excellent place from which to launch an even brighter future. I and the whole team at OmniAb look forward to building a stronger and more successful company that benefits our stockholders, our other stakeholders and the world.

							Sincerely,
							Matthew W. Foehr President and Chief Executive Officer OmniAb, Inc.

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AVISTA PUBLIC ACQUISITION CORP. II

A Cayman Islands Exempted Company
(Company Number 306402)
65 East 55th Street, 18th Floor
New York, NY 10022

NOTICE OF EXTRAORDINARY GENERAL MEETING
TO BE HELD ON [•], 2022

TO THE SHAREHOLDERS OF AVISTA PUBLIC ACQUISITION CORP. II:

NOTICE IS HEREBY GIVEN that an extraordinary general meeting (the “extraordinary general meeting”) of Avista Public Acquisition Corp. II, a Cayman Islands exempted company, company number 306402 (“APAC”), will be held at the offices of Weil, Gotshal & Manges LLP, located at 767 Fifth Avenue, New York, NY 10153, at 10:00 a.m. Eastern Time, on [•], 2022. Cayman Islands law requires there to be a physical location for the extraordinary general meeting. However, given the ongoing global pandemic, the extraordinary general meeting will also be held virtually via live webcast. As such, APAC shareholders may attend the extraordinary general meeting by visiting the extraordinary general meeting website at https://www.cstproxy.com/avistapac/2022, where they will be able to listen to the meeting live and vote during the meeting. We are pleased to utilize virtual shareholder meeting technology to (i) provide ready access and cost savings for APAC shareholders and APAC and (ii) protect the health and safety of our shareholders. You are cordially invited to attend the extraordinary general meeting, which will be held for the following purposes:

Proposal No. 1 — The Business Combination Proposal — to consider and vote upon a proposal to approve by special resolution and adopt (i) the Agreement and Plan of Merger, dated as of March 23, 2022 (the “Merger Agreement”), by and among APAC, Ligand Pharmaceuticals Incorporated, a Delaware corporation (“Ligand”), OmniAb, Inc., a Delaware corporation and wholly-owned subsidiary of Ligand (“OmniAb”), and Orwell Merger Sub Inc., a Delaware corporation and wholly-owned subsidiary of APAC (“Merger Sub”), (ii) the Transaction Documents (as defined in the Merger Agreement) and (iii) each of the transactions contemplated thereby, in each case, in accordance with the terms and subject to the conditions set forth in the Merger Agreement and such Transaction Documents, as more fully described elsewhere in the accompanying proxy statement/prospectus/information statement (the “Business Combination Proposal”);

Proposal No. 2 — The Domestication Proposal — to consider and vote upon a proposal to approve by special resolution the change of APAC’s jurisdiction of incorporation (the “Domestication”), by deregistering as an exempted company in the Cayman Islands and continuing and domesticating under the name “OmniAb, Inc.” as a corporation incorporated under the laws of the State of Delaware (the “Domestication Proposal”);

Proposal No. 3 — The Organizational Documents Proposal — to consider and vote upon a proposal to approve by special resolution and adopt the proposed new certificate of incorporation (the “Proposed Certificate of Incorporation”) and the proposed new bylaws (the “Proposed Bylaws”) of APAC after giving effect to the Domestication (“New OmniAb”) (the “Organizational Documents Proposal”);

Proposal No. 4 — The Non-Binding Governance Proposals — to consider and vote upon, on a non-binding advisory basis, certain material differences between APAC’s Amended and Restated Memorandum and Articles of Association (as it may be amended from time to time, the “Cayman Constitutional Documents”) and the Proposed Certificate of Incorporation and Proposed Bylaws, presented separately in accordance with the United States Securities and Exchange Commission requirements (collectively, the “Non-Binding Governance Proposals”);

Proposal No. 5 — The Stock Issuance Proposal — to consider and vote upon a proposal to approve by ordinary resolution, for the purposes of complying with the applicable provisions of Nasdaq Rule 5635, the issuance of shares of common stock, par value $0.0001, of New OmniAb pursuant to (a) the Domestication, (b) the PIPE Investment, (c) the Redemption Backstop and (d) the Merger, as each of

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the capitalized terms used in clauses (b), (c) and (d) are defined in the Merger Agreement and described in the accompanying proxy statement/prospectus/information statement (the “Stock Issuance Proposal”);

Proposal No. 6 — The Incentive Plan Proposal — to consider and vote upon a proposal to approve by ordinary resolution, the OmniAb, Inc. 2022 Incentive Award Plan (the “Incentive Plan Proposal”);

Proposal No. 7 — The ESPP Proposal — to consider and vote upon a proposal to approve by ordinary resolution, the OmniAb, Inc. 2022 Employee Stock Purchase Plan (the “ESPP Proposal”);

Proposal No. 8 — The Director Election Proposal — to consider and vote upon a proposal to elect seven directors to serve staggered terms on the New OmniAb Board upon the consummation of the Business Combination until the first, second and third annual meeting of stockholders following the date of effectiveness of the Proposed Certificate of Incorporation, as applicable, or until the election and qualification of their respective successors in office, subject to their earlier death, resignation or removal (the “Director Election Proposal”); and

Proposal No. 9 — The Adjournment Proposal — to consider and vote upon a proposal to approve the adjournment of the extraordinary general meeting to a later date or dates, if necessary, to permit further solicitation and vote of proxies in the event that there are insufficient shares represented to constitute a quorum necessary to conduct business at the extraordinary general meeting or for the approval of one or more proposals at the extraordinary general meeting or to the extent necessary to ensure that any required supplement or amendment to the accompanying proxy statement/prospectus/information statement is provided to APAC shareholders (the “Adjournment Proposal”).

Each of Proposals No. 1 through 3 and 5 through 8 (the “Condition Precedent Proposals”) are cross-conditioned on the approval of the others. Proposal No. 9 is not conditioned upon the approval of any other proposal set forth in this proxy statement/prospectus/information statement. Proposal No. 4 is constituted of non-binding advisory proposals.

These items of business are described in the accompanying proxy statement/prospectus/information statement, which we encourage you to read carefully and in its entirety before voting.

Only holders of record of APAC ordinary shares at the close of business on September 1, 2022 are entitled to notice of and to vote and have their votes counted at the extraordinary general meeting and any adjournment of the extraordinary general meeting.

The accompanying proxy statement/prospectus/information statement and accompanying proxy card is being provided to APAC’s shareholders in connection with the solicitation of proxies to be voted at the extraordinary general meeting and at any adjournment of the extraordinary general meeting. Whether or not you plan to attend the extraordinary general meeting, all of APAC’s shareholders are urged to read this proxy statement/prospectus/information statement, including the Annexes and the documents referred to herein, carefully and in their entirety. You should also carefully consider the risk factors described in “Risk Factors” beginning on page 92 of the accompanying proxy statement/prospectus/information statement.

After careful consideration, the APAC Board has unanimously approved the Business Combination and unanimously recommends that shareholders vote “FOR” the adoption of the Business Combination Proposal and the Domestication Proposal and “FOR” all other proposals to be presented to APAC’s shareholders at the extraordinary general meeting. When you consider the recommendation of these proposals by the APAC Board, you should keep in mind that APAC’s directors and officers have interests therein that may conflict with your interests as a shareholder. See the section entitled “Shareholder Proposal No. 1 — The Business Combination Proposal — Interests of APAC’s Directors and Executive Officers in the Business Combination” in the accompanying proxy statement/prospectus/information statement for a further discussion of these considerations.

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Pursuant to the Cayman Constitutional Documents, a holder of public shares (as defined in the accompanying proxy statement/prospectus/information statement) (a “public shareholder”) may request of APAC that APAC redeem all or a portion of its public shares for cash if the Business Combination is consummated. As a holder of public shares, you will be entitled to receive cash for any public shares to be redeemed only if you:

(i)

(a) hold public shares, or (b) if you hold public shares through units, you elect to separate your units into the underlying public shares and public warrants prior to exercising your redemption rights with respect to the public shares;

(ii)

submit a written request to Continental Stock Transfer & Trust (“Continental”), APAC’s transfer agent, in which you (i) request that New OmniAb redeem all or a portion of your New OmniAb Common Stock for cash, and (ii) identify yourself as the beneficial holder of the New OmniAb Common Stock and provide your legal name, phone number and address; and

(iii)

deliver your public shares to Continental, APAC’s transfer agent, physically or electronically through The Depository Trust Company (“DTC”).

Holders must complete the procedures for electing to redeem their public shares in the manner described above prior to 5:00 p.m., Eastern Time, on [•], 2022 (two business days before the extraordinary general meeting) in order for their shares to be redeemed.

Holders of units must elect to separate the units into the underlying public shares and warrants prior to exercising redemption rights with respect to the public shares. If holders hold their units in an account at a brokerage firm or bank, holders must notify their broker or bank that they elect to separate the units into the underlying public shares and warrants, or if a holder holds units registered in its own name, the holder must contact Continental, APAC’s transfer agent, directly and instruct them to do so. Public shareholders may elect to redeem public shares regardless of how they vote in respect of the Business Combination Proposal. If the Business Combination is not consummated, the public shares will be returned to the respective holder, broker or bank.

If the Business Combination is consummated, and if a public shareholder properly exercises its right to redeem all or a portion of the public shares that it holds and timely delivers its shares to Continental, APAC’s transfer agent, APAC will redeem such public shares for a per-share price, payable in cash, equal to the pro rata portion of the trust account established at the consummation of our initial public offering (the “trust account”), calculated as of two business days prior to the consummation of the Business Combination. For illustrative purposes, as of [•], 2022, this would have amounted to approximately $[•] per issued and outstanding public share. If a public shareholder exercises its redemption rights in full, then it will be electing to exchange its public shares for cash and will no longer own public shares. The redemption takes place following the Domestication and, accordingly, it is shares of New OmniAb Common Stock that will be redeemed promptly after consummation of the Business Combination. See “Extraordinary General Meeting of APAC — Redemption Rights” in the accompanying proxy statement/prospectus/information statement for a detailed description of the procedures to be followed if you wish to redeem your public shares for cash.

Avista Acquisition LP II, a Cayman Islands exempted limited partnership and shareholder of APAC (the “Sponsor”), and each director of APAC have agreed to, among other things, vote in favor of the Business Combination Proposal and the transactions contemplated thereby, including the other Condition Precedent Proposals, and to waive their redemption rights in connection with the underwriting agreement entered into in connection with the initial public offering. The APAC Class B Ordinary Shares held by the Sponsor and such other persons will be excluded from the pro rata calculation used to determine the per-share

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redemption price. As of the date of the accompanying proxy statement/prospectus/information statement, the Sponsor and APAC’s directors, collectively, own 20% of the issued and outstanding ordinary shares of APAC.

The approval of the Business Combination Proposal, Domestication Proposal and the Organizational Documents Proposal each requires a special resolution under Cayman Islands law, being the affirmative vote of the holders of at least two-thirds majority of the APAC ordinary shares represented in person, virtually or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting. With respect to the Domestication Proposal, a holder of APAC Class B Ordinary Shares shall have ten votes for every APAC Class B Ordinary Share of which he or she is the holder and a holder of APAC Class A Ordinary Shares shall have one vote for every APAC Class A Ordinary Share of which he or she is the holder. The Non-Binding Governance Proposals (which are comprised of non-binding advisory proposals), the Director Election Proposal, the Stock Issuance Proposal, the Incentive Plan Proposal, the ESPP Proposal and the Adjournment Proposal each requires an ordinary resolution under Cayman Islands law, being the affirmative vote of the holders of a majority of the ordinary shares represented in person, virtually or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting. With respect to the Director Election Proposal, only the holders of the APAC Class B Ordinary Shares are entitled to vote.

If you sign, date and return your proxy card without indicating how you wish to vote, your proxy will be voted FOR each of the proposals presented at the extraordinary general meeting. If you fail to return your proxy card or fail to instruct your bank, broker or other nominee how to vote, and do not attend the extraordinary general meeting either virtually or in person, the effect will be, among other things, that your shares will not be counted for purposes of determining whether a quorum is present at the extraordinary general meeting and will not be voted. An abstention will be counted towards the quorum requirement but will not count as a vote cast at the extraordinary general meeting. A broker non-vote, while considered present for the purposes of establishing a quorum, will not count as a vote cast at the extraordinary general meeting. If you are a shareholder of record and you attend the extraordinary general meeting and wish to vote virtually or in person, you may withdraw your proxy and vote either virtually or in person.

Your attention is directed to the remainder of the accompanying proxy statement/prospectus/information statement following this notice (including the Annexes and other documents referred to herein) for a more complete description of the proposed Business Combination and related transactions and each of the proposals. You are encouraged to read the accompanying proxy statement/prospectus/information statement carefully and in its entirety, including the Annexes and other documents referred to herein. If you have any questions or need assistance voting your ordinary shares, please contact D.F. King & Co., Inc., our proxy solicitor, by calling (888) 887-0082, or banks and brokers can call collect at (212) 269-5550 or by emailing AHPA@dfking.com.

Thank you for your participation. We look forward to your continued support.

By Order of the Board of Directors of Avista Public Acquisition Corp. II, [•], 2022

Thompson Dean
Chairman of the APAC Board

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REFERENCES TO ADDITIONAL INFORMATION

This proxy statement/prospectus/information statement incorporates important business and financial information that is not included in or delivered with this proxy statement/prospectus/information statement. This information is available for you to review through the SEC’s website at www.sec.gov.

You may request copies of this proxy statement/prospectus/information statement and any of the documents incorporated by reference into this proxy statement/prospectus/information statement or other publicly available information concerning APAC, without charge, by written request to APAC at Avista Public Acquisition Corp. II, 65 East 55th Street, 18th Floor, New York, NY 10022, or by telephone request at (212)-593-6900; or D.F. King & Co., Inc., APAC’s proxy solicitor, by calling (888) 877-0082 or banks and brokers can call collect at (212) 269-5550, or by emailing AHPA@dfking.com; or from the SEC through the SEC website at the address provided above.

In order for APAC’s shareholders to receive timely delivery of the documents in advance of the extraordinary general meeting of APAC to be held on [•], 2022, you must request the information no later than [•], 2022, five business days prior to the date of the extraordinary general meeting.

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SELECTED DEFINITIONS

Unless otherwise stated in this proxy statement/prospectus/information statement or the context otherwise requires, references to:

•

“A&R FPA” are to that certain Amended and Restated Forward Purchase Agreement, dated March 23, 2022, by and among APAC, the Sponsor and OmniAb, which is attached hereto as Annex D;

•

“A&R Registration Rights Agreement” are to the Amended and Restated Registration and Stockholder Rights Agreement to be entered into at the Closing by and among Ligand, APAC, the Sponsor, the existing holders party to the Original Registration Rights Agreement and the new holders party thereto, the form of which is attached to this proxy statement/prospectus/information statement as Annex G;

•

“Aggregate Merger Consideration” are to a number of shares of New OmniAb Common Stock equal to the quotient obtained by dividing (i) the sum of (a) $850,000,000, plus (b) the aggregate exercise price of the OmniAb Options that are issued and outstanding immediately prior to the Effective Time, by (ii) $10.00, provided, that if the “Aggregate Merger Consideration” as so calculated (together with the number of Included OmniAb Shares, calculated including shares underlying OmniAb Options, as applicable) would result in the product of (x) the Base Exchange Ratio, multiplied by (y) $10.00, being less than the exercise price of any of the OmniAb Options issued and outstanding as of immediately prior to the Effective Time, then the calculation described in this definition shall be repeated by excluding the exercise price of all of the OmniAb Options with the highest exercise price per share from the calculation of the aggregate exercise price described in clause (i)(b) of this definition and excluding any shares underlying such OmniAb Options from the calculation of Included OmniAb Shares, in each case, on an iterative basis until the resulting calculations of Aggregate Merger Consideration and Included OmniAb Shares cause the product of (I) the Base Exchange Ratio and (II) $10.00 to be equal to or in excess of the exercise price of all of the OmniAb Options included in such calculations, and the Aggregate Merger Consideration so calculated shall be the “Aggregate Merger Consideration”;

•

“APAC,” “Company,” “we,” “us” and “our” are to Avista Public Acquisition Corp. II, a Cayman Islands exempted company prior to its domestication as a corporation in the State of Delaware, and, following its domestication, to New OmniAb or OmniAb, Inc.;

•

“APAC Board” are to the board of directors of APAC;

•

“APAC Class A Ordinary Shares” are to APAC’s Class A ordinary shares, par value $0.0001 per share;

•

“APAC Class B Ordinary Shares” are to APAC’s Class B ordinary shares, par value $0.0001 per share;

•

“APAC Private Placement Warrants” are to the 8,233,333 APAC Warrants that were issued to the Sponsor in a private placement in connection with APAC’s initial public offering and are issued and outstanding immediately prior to the Domestication;

•

“APAC Public Warrants” are to the 7,666,667 APAC Warrants, a fraction equal to one-third of which was included in each unit sold as part of APAC’s initial public offering and are issued and outstanding immediately prior to the Domestication;

•

“APAC Units” are to each issued and outstanding unit of APAC prior to the Domestication;

•

“APAC Warrants” are to warrants to purchase one (1) APAC Class A Ordinary Share at an exercise price of $11.50;

•

“Base Exchange Ratio” are to the quotient obtained by dividing (i) the number of shares constituting the Aggregate Merger Consideration by (ii) the number of Included OmniAb Shares;

•

“Business Combination” are to the combination of APAC and OmniAb pursuant to the transactions provided for and contemplated in the Merger Agreement;

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•

“Cayman Constitutional Documents” are to APAC’s Amended and Restated Memorandum and Articles of Association, as amended from time to time;

•

“Cayman Islands Companies Act” are to the Companies Act (As Revised) of the Cayman Islands;

•

“Closing” are to the closing of the Business Combination;

•

“Condition Precedent Approvals” are to the approval at the extraordinary general meeting of the Condition Precedent Proposals;

•

“Condition Precedent Proposals” are to the Business Combination Proposal, the Domestication Proposal, the Organizational Documents Proposal, the Stock Issuance Proposal, the Incentive Plan Proposal, the ESPP Proposal, and the Director Election Proposal, collectively;

•

“Continental” are to Continental Stock Transfer & Trust Company;

•

“DGCL” are to the General Corporation Law of the State of Delaware;

•

“Domestication” are to the domestication of APAC as a corporation incorporated in the State of Delaware;

•

“Earnout Period” are to the period commencing on the date of the Closing and ending on the date that is five years after the date of the Closing;

•

“Earnout Exchange Ratio” are to the quotient obtained by dividing (i) 15,000,000 by (ii) the number of Fully-Diluted OmniAb Shares;

•

“Effective Time” are to the time at which the Merger shall become effective in accordance with the terms of the Merger Agreement;

•

“Employee Matters Agreement” are to that certain Employee Matters Agreement, dated March 23, 2022, as amended by that certain Amended and Restated Employee Matters Agreement, dated as of August 18, 2022, by and among APAC, Ligand, Merger Sub and OmniAb;

•

“Exchange Act” are to the Securities Exchange Act of 1934, as amended;

•

“extraordinary general meeting” are to the extraordinary general meeting of APAC duly called by the APAC Board and held for the purpose of considering and voting upon the proposals set forth in this proxy statement/prospectus/information statement;

•

“Forward Purchase” are to the purchase of shares and warrants of New OmniAb Common Stock to be issued to the Sponsor in a private placement transaction following the Domestication and immediately prior to the Merger pursuant to the A&R FPA, excluding the Redemption Backstop;

•

“founder shares” are to the APAC Class B Ordinary Shares, and the shares of New OmniAb Common Stock to be issued to the Sponsor and certain related parties in respect thereof in connection with the Domestication;

•

“Fully-Diluted OmniAb Shares” are to (without duplication) the aggregate number of shares of OmniAb Common Stock that are (i) issued and outstanding immediately prior to the Effective Time or (ii) issuable upon, or subject to, the exercise or settlement of OmniAb Options (whether or not then vested or exercisable), OmniAb RSUs and OmniAb PSUs, in each case, that are issued and outstanding immediately prior to the Effective Time;

•

“GAAP” are to accounting principles generally accepted in the United States of America;

•

“HSR Act” are to the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended;

•

“Included OmniAb Shares” are to (without duplication) the aggregate number of shares of OmniAb Common Stock that are (i) issued and outstanding immediately prior to the Effective Time or (ii) issuable upon, or subject to, the exercise or settlement (as applicable) of OmniAb Options (whether or not then vested or exercisable, but excluding any OmniAb Options excluded from the definition of “Aggregate Common Consideration Shares” set forth in the Merger Agreement pursuant to the proviso thereto), OmniAb RSUs and OmniAb PSUs, in each case, that are issued and outstanding immediately prior to the Effective Time;

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•

“initial public offering” are to APAC’s initial public offering, which was consummated on August 12, 2021;

•

“Investment Company Act” are to the Investment Company Act of 1940, as amended;

•

“IPO registration statement” are to the Registration Statement on Form S-1 (333-257177) filed by APAC in connection with its initial public offering, which became effective on August 9, 2021;

•

“IRS” are to the U.S. Internal Revenue Service;

•

“JOBS Act” are to the Jumpstart Our Business Startups Act of 2012;

•

“Ligand” are to Ligand Pharmaceuticals Incorporated, a Delaware corporation;

•

“Ligand Board” are to the board of directors of Ligand;

•

“Ligand Common Stock” are to shares of common stock of Ligand, par value $0.001 per share;

•

“Ligand Contribution” are to the cash contribution of $15,000,000, less certain transaction and other expenses, by Ligand to OmniAb prior to the Distribution pursuant to the Separation Agreement;

•

“Ligand Convertible Notes” are to Ligand’s 0.75% Convertible Senior Notes due 2023;

•

“Ligand Record Date” are to the date to be determined by the Ligand Board as the record date for determining stockholders of Ligand entitled to receive shares of OmniAb Common Stock in the Distribution;

•

“Merger” are to the merger of Merger Sub with and into OmniAb, with OmniAb surviving the merger as a wholly-owned subsidiary of APAC in accordance with the terms and subject to the conditions set forth in the Merger Agreement;

•

“Merger Agreement” are to that certain Agreement and Plan of Merger, dated as of March 23, 2022, by and among APAC, Ligand, Merger Sub and OmniAb, a copy of which is attached to this proxy statement/prospectus/information statement as Annex A;

•

“Merger Sub” are to Orwell Merger Sub Inc., a Delaware corporation and a wholly-owned subsidiary of APAC;

•

“Nasdaq” are to the Nasdaq Capital Market;

•

“New OmniAb” are to APAC, following the Domestication;

•

“New OmniAb Board” are to the board of directors of New OmniAb;

•

“New OmniAb Common Stock” are to shares of common stock of New OmniAb, par value $0.0001 per share;

•

“New OmniAb Equity Award” are to equity awards into which OmniAb Equity Awards are converted upon the Closing;

•

“New OmniAb Options” are to options to purchase shares of New OmniAb Common Stock;

•

“New OmniAb PSUs” are to performance-vesting restricted stock units relating to shares of New OmniAb Common Stock;

•

“New OmniAb RSUs” are to restricted stock units relating to shares of New OmniAb Common Stock;

•

“New OmniAb Warrants” are to warrants to purchase one share of New OmniAb Common Stock at an exercise price of $11.50, including those issued as a matter of law upon conversion of the APAC Warrants at the time of the Domestication;

•

“OmniAb” are to OmniAb, Inc., a Delaware corporation and, prior to the Distribution, a wholly-owned subsidiary of Ligand, and after the Distribution, include the ownership of the OmniAb Business;

•

“OmniAb Business” are to Ligand’s antibody discovery business;

•

“OmniAb Common Stock” are to shares of common stock of OmniAb, par value $0.001 per share, outstanding prior to the Merger;

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“OmniAb Earnout Shares” are to the earnout consideration in the form of 15,000,000 shares of New OmniAb Common Stock that the holders of OmniAb Common Stock and OmniAb Equity Awards will receive at the Closing, all of which will be automatically forfeited for no consideration if an applicable OmniAb Triggering Event has not occurred with respect to such OmniAb Earnout Shares during the period from the date of the Closing to and including the fifth anniversary of the date of the Closing;

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“OmniAb Equity Awards” are to, collectively, the OmniAb Options, OmniAb RSUs and OmniAb PSUs;

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“OmniAb Options” are to options to purchase shares of OmniAb Common Stock;

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“OmniAb PSUs” are to performance-vesting restricted stock units relating to shares of OmniAb Common Stock;

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“OmniAb RSUs” are to restricted stock units relating to shares of OmniAb Common Stock;

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“OmniAb Triggering Event” are to (a) with respect to 50% of the OmniAb Earnout Shares, the date on which the VWAP equals or exceeds $12.50 on any 20 trading days in any 30 consecutive trading-day period, and (b) with respect any OmniAb Earnout Shares for which an OmniAb Triggering Event has not occurred with respect to clause (a), the date on which the VWAP equals or exceeds $15.00 on any 20 trading days in any 30 consecutive trading-day period; provided, that in the event of a Change of Control (as defined in the Merger Agreement) between the date of the Closing to and including the fifth anniversary of the date of the Closing pursuant to which New OmniAb or any of its stockholders have the right to receive, directly or indirectly, cash, securities or other property attributing a value of at least $12.50 (with respect to 50% of the OmniAb Earnout Shares) or $15.00 (with respect to all OmniAb Earnout Shares) per share of New OmniAb Common Stock, and such Change of Control has been approved by a majority of the independent directors of the New OmniAb Board, then an OmniAb Triggering Event shall be deemed to have occurred immediately prior to such Change of Control;

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“ordinary shares” are to the APAC Class A Ordinary Shares and the APAC Class B Ordinary Shares, collectively;

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“Person” are to any individual, firm, corporation, partnership, limited liability company, incorporated or unincorporated association, joint venture, joint stock company, governmental authority or instrumentality or other entity of any kind;

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“pro forma” are to giving pro forma effect to the Business Combination;

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“Proposed Bylaws” are to the proposed bylaws of New OmniAb upon the effective date of the Domestication attached to this proxy statement/prospectus/information statement as Annex I;

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“Proposed Certificate of Incorporation” are to the proposed certificate of incorporation of New OmniAb upon the effective date of the Domestication attached to this proxy statement/prospectus/information statement as Annex H;

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“Proposed Organizational Documents” are to the Proposed Certificate of Incorporation and the Proposed Bylaws;

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“public shareholders” are to holders of public shares, whether acquired in APAC’s initial public offering or acquired in the secondary market;

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“public shares” are to the APAC Class A Ordinary Shares (including those included in the units) that were offered and sold by APAC in its initial public offering and registered pursuant to the IPO registration statement or the shares of New OmniAb Common Stock issued as a matter of law upon the conversion thereof at the time of the Domestication, as the context requires;

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“redemption” are to each redemption of public shares for cash pursuant to the Cayman Constitutional Documents and the Proposed Organizational Documents;

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“Redemption Backstop” are to the purchase of shares and warrants of New OmniAb Common Stock, if any, to be issued to the Sponsor in a private placement transaction following the

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Domestication and immediately prior to the Merger pursuant to the A&R FPA to the extent necessary to backstop redemptions;

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“Registration Rights Agreement” are to the Amended and Restated Registration and Stockholders Rights Agreement to be entered into at the Closing, by and among APAC, the Sponsor, the directors of APAC, and certain directors and officers of OmniAb and Ligand;

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“Sarbanes Oxley Act” are to the Sarbanes-Oxley Act of 2002;

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“SEC” are to the United States Securities and Exchange Commission;

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“Securities Act” are to the Securities Act of 1933, as amended;

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“Sponsor” are to Avista Acquisition LP II, a Cayman Islands exempted limited partnership;

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“Sponsor Insider Agreement” are to that certain Sponsor Insider Letter Agreement, dated as of March 23, 2022, by and between APAC, the Sponsor, OmniAb and certain insiders of APAC, a copy of which is attached to this proxy statement/prospectus/information statement as Annex C;

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“Sponsor Earnout Shares” are to the founder shares beneficially owned by Sponsor on March 23, 2022, in an aggregate number equal to (i) 1,916,667 minus (ii) (A) 718,750 multiplied by (B) a number the numerator of which is the number of shares of New OmniAb Common Stock actually purchased pursuant to the Redemption Backstop in connection with the Closing and the denominator of which is 10,000,000, all or fifty percent of which shares will be automatically forfeited for no consideration if an applicable Sponsor Triggering Event has not occurred with respect to such Sponsor Earnout Shares during the period from the date of the Closing to and including the fifth anniversary of the date of the Closing;

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“Sponsor Triggering Event” are to, (a) with respect to 50% of the Sponsor Earnout Shares, the date on which the VWAP equals or exceeds $12.50 on any 20 trading days in any 30 consecutive trading-day period, and (b) with respect any Sponsor Earnout Shares for which a Sponsor Triggering Event has not occurred with respect to clause (a), the date on which the VWAP equals or exceeds $15.00 on any 20 trading days in any 30 consecutive trading-day period; provided, that in the event of a Change of Control (as defined in the Merger Agreement) between the date of the Closing to and including the fifth anniversary of the date of the Closing pursuant to which New OmniAb or any of its stockholders have the right to receive, directly or indirectly, cash, securities or other property attributing a value of at least $12.50 (with respect to 50% of the Sponsor Earnout Shares) or $15.00 (with respect to all Sponsor Earnout Shares) per share of New OmniAb Common Stock, as agreed in good faith by the Sponsor and the New OmniAb Board, then a Sponsor Triggering Event shall be deemed to have occurred immediately prior to such Change of Control (as defined in the Merger Agreement);

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“Tax Matters Agreement” are to the Tax Matters Agreement to be entered into at the Closing by and among APAC, Ligand and OmniAb, the form of which is attached proxy statement/prospectus/information statement as Annex E;

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“Transaction Documents” are to the Separation Agreement, the Employee Matters Agreement, the Tax Matters Agreement, the Transition Services Agreements, the A&R FPA, the Sponsor Insider Agreement and the A&R Registration Rights Agreement, in each case, including all annexes, exhibits, schedules, attachments and appendices thereto, and any certificate or other instrument delivered by any party to any other party pursuant to the Merger Agreement or any of the foregoing;

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“Transition Services Agreements” are to each of the Transition Services Agreements to be entered into at the Closing by and between Ligand and OmniAb, the forms of which are attached hereto as Annex F-1 and Annex F-2;

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“trust account” are to the trust account established at the consummation of APAC’s initial public offering and maintained by Continental, acting as trustee;

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“Treasury Shares” are to the shares of OmniAb Common Stock held in OmniAb’s treasury, which will be cancelled for no consideration in connection with the Merger;

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This proxy statement/prospectus/information statement contains forward-looking statements. The words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “might,” “plan,” “possible,” “potential,” “predict,” “project,” “should,” “would” and similar expressions may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. All statements other than statements of historical facts contained in this proxy statement/prospectus/information statement, including statements regarding the expected timing and structure of the Separation, Distribution and Merger, the ability of the parties to complete the Business Combination, the expected benefits of the Business Combination, the tax consequences of the Separation, Distribution and Merger, the amount of gross proceeds expected to be available to OmniAb after the Closing and giving effect to any redemptions by APAC shareholders, OmniAb’s future results of operations and financial position, business strategy and its expectations regarding the application of, and the rate and degree of market acceptance of, the OmniAb technology platform and other technologies, OmniAb’s expectations regarding the addressable markets for our technologies, including the growth rate of the markets in which it operates, the potential for and timing of receipt of milestones and royalties under OmniAb’s license agreements with partners, are forward-looking statements. These forward-looking statements are not guarantees of future performance, conditions or results, and involve a number of known and unknown risks, uncertainties, assumptions and other important factors, many of which are outside the control of Ligand, OmniAb and APAC, that could cause actual results or outcomes to differ materially from those discussed in the forward-looking statements.

The forward-looking statements contained in this proxy statement/prospectus/information statement and in any document incorporated by reference in this proxy statement/prospectus/information statement are based on current expectations and beliefs concerning future developments and their potential effects on APAC, Ligand or OmniAb. There can be no assurance that future developments affecting APAC, Ligand or OmniAb will be those that APAC, Ligand or OmniAb have anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond APAC’s control or the control of OmniAb or Ligand) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, those factors described under the heading “Risk Factors” beginning on page 92 of this proxy statement/prospectus/information statement and the following:

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the risk that the Business Combination may not be completed in a timely manner or at all, which may adversely affect the price of Ligand’s or APAC’s securities;

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the risk that APAC shareholder approval of the Condition Precedent Proposals is not obtained;

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the inability to recognize the anticipated benefits of the Business Combination, which may be affected by, among other things, the amount of funds available to New OmniAb following any redemptions by APAC’s shareholders, after giving effect to the Forward Purchase and the Redemption Backstop;

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the failure to receive certain governmental and regulatory approvals;

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the occurrence of any event, change or other circumstance that could give rise to the termination of the Merger Agreement;

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changes in general economic conditions, geopolitical risk, including as a result of the COVID-19 pandemic or the conflict between Russia and Ukraine;

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the outcome of litigation related to or arising out of the Business Combination, or any adverse developments therein or delays or costs resulting therefrom;

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the effect of the announcement or pendency of the transactions on Ligand’s, OmniAb’s or APAC’s business relationships, operating results, and businesses generally;

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the ability to continue to meet Nasdaq’s listing standards following the consummation of the Business Combination;

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the costs related to the Business Combination;

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that the price of APAC’s or Ligand’s securities may be volatile due to a variety of factors, including Ligand’s, APAC’s or OmniAb’s inability to implement their business plans or meet or exceed their financial projections and changes in the combined capital structure; and

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factors relating to the business, operations and financial performance of OmniAb and its subsidiaries, including:

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as a result of the Separation, OmniAb will lose Ligand’s brand, reputation, capital base and other resources, and may experience difficulty operating as a standalone company;

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the anticipated benefits of the Separation may not be achieved;

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OmniAb’s historical combined financial data and pro forma financial statements are not necessarily representative of the results OmniAb would have achieved as a standalone company and may not be a reliable indicator of its future results;

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OmniAb’s operating results and financial performance;

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acceptance by new and existing partners in OmniAb’s market;

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OmniAb’s future success is dependent on the eventual approval and commercialization of products developed by its partners for which we have no control over the clinical development plan, regulatory strategy or commercialization efforts;

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OmniAb’s ability to manage and grow its business and execution of its business and growth strategies;

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risks arising from changes in technology;

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the competitive environment in the life sciences and biotechnology platform market;

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failure to maintain, protect and defend our intellectual property rights;

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changes in government laws and regulations, including laws governing intellectual property, and the enforcement thereof affecting our business;

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difficulties with performance of third parties we will rely on for our business growth;

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difficulties developing and sustaining relationships with commercial counterparties;

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OmniAb may not be able to engage in certain transactions and equity issuances following the Distribution; and

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OmniAb may have certain indemnification obligations to Ligand under the Tax Matters Agreement.

Should one or more of these risks or uncertainties materialize, or should any of APAC’s assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. None of APAC, Ligand or OmniAb undertakes any obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as may be required under applicable securities laws.

Before any APAC shareholder grants its proxy or instructs how its vote should be cast or votes on the proposals to be put to the extraordinary general meeting, such shareholder should be aware that the occurrence of the events described in the “Risk Factors” section and elsewhere in this proxy statement/prospectus/information statement may adversely affect APAC.

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QUESTIONS AND ANSWERS

The questions and answers below highlight only selected information from this document and only briefly address some commonly asked questions about the proposals to be presented at the extraordinary general meeting, including with respect to the proposed Business Combination. The following questions and answers do not include all the information that is important to APAC’s shareholders. APAC urges shareholders to read this proxy statement/prospectus/information statement, including the Annexes and the other documents referred to herein, carefully and in their entirety to fully understand the proposed Business Combination and the voting procedures for the extraordinary general meeting.

How do I attend the meeting virtually?

The extraordinary general meeting will be accessible virtually via a live webcast at https://www.cstproxy.com/avistapac/2022, at 10:00 a.m., Eastern Time, on [•], 2022. To participate in the virtual meeting, including the voting of shares, APAC shareholders of record will need (a) the 12-digit control number included on their proxy card or instructions that accompanied their proxy materials, if applicable, or (b) to obtain a proxy form from their broker, bank or other nominee.

The extraordinary general meeting webcast will begin promptly at 10:00 a.m., Eastern Time. APAC shareholders are encouraged to access the extraordinary general meeting prior to the start time. If you encounter any difficulties accessing the virtual meeting or during the meeting time, please call the technical support number that will be posted on the virtual meeting login page.

Can I attend the extraordinary general meeting in person?

Yes. APAC shareholders will be able to attend the extraordinary general meeting in person, which will be held on [•], 2022, at 10:00 a.m., Eastern Time, at the offices of Weil, Gotshal & Manges LLP, located at 767 Fifth Avenue, New York, NY 10153. However, given the ongoing global pandemic, APAC encourages its shareholders to attend via live webcast on the Internet.

Why am I receiving this proxy statement/prospectus/information statement?

You are receiving these materials because you are a shareholder of record or a beneficial holder of APAC on September 1, 2022, the record date (the “APAC Record Date”) for the extraordinary general meeting. APAC and Ligand have agreed to combine Ligand’s OmniAb Business with APAC in a series of transactions subject to the terms and conditions of the Separation Agreement, the Merger Agreement and the other Transaction Documents. Copies of the Separation Agreement and the Merger Agreement are attached as Annexes B and A, respectively. APAC shareholders are being asked to consider and vote upon a proposal to approve the Business Combination and a number of other proposals. See the section entitled “Shareholder Proposal No. 1 — The Business Combination Proposal” for more detail.

THE VOTE OF SHAREHOLDERS IS IMPORTANT. SHAREHOLDERS ARE ENCOURAGED TO VOTE AS SOON AS POSSIBLE AFTER CAREFULLY REVIEWING THIS PROXY STATEMENT/PROSPECTUS/INFORMATION STATEMENT IN ITS ENTIRETY, INCLUDING THE ANNEXES AND THE ACCOMPANYING FINANCIAL STATEMENTS OF APAC AND OMNIAB.

What are the transactions described in this document?

On March 23, 2022, APAC, Ligand, OmniAb and Merger Sub entered into the Merger Agreement, and, on the same day, APAC, Ligand and OmniAb entered into the Separation Agreement. These agreements provide for Ligand to combine the OmniAb Business with APAC in a transaction commonly referred to as a “Reverse Morris Trust” transaction. The principal transactions to effect the Business Combination include the following:

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Domestication. APAC’s jurisdiction of incorporation will be changed by its deregistering as an exempted company in the Cayman Islands and continuing and domesticating as a corporation incorporated under the laws of the State of Delaware at least one (1) business day prior to the consummation of the Merger. In connection with the consummation of the Domestication, APAC will change its name to “OmniAb, Inc.” As a result of and upon the effective time of the Domestication, (1) each then issued and outstanding APAC Class A Ordinary Share, will convert automatically,

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on a one-for-one basis, into a share of New OmniAb Common Stock, (2) each then issued and outstanding APAC Class B Ordinary Share will convert automatically, on a one-for-one basis, into a share of New OmniAb Common Stock, (3) each then issued and outstanding APAC Warrant will convert automatically into a New OmniAb Warrant pursuant to the Warrant Agreement, and (4) each then issued and outstanding APAC Unit, will separate and convert automatically into one share of New OmniAb Common Stock and one-third of one New OmniAb Warrant.

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Separation. Ligand will transfer the OmniAb Business, including certain related subsidiaries of Ligand, to OmniAb and make a contribution to the capital of OmniAb of $15,000,000 less certain transaction and other expenses.

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Distribution. Following the Separation and on the day of the Merger described below, Ligand will distribute to Ligand stockholders 100% of the OmniAb Common Stock.

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A&R Forward Purchase Agreement. New OmniAb will issue and sell to the Sponsor 1,500,000 shares of New OmniAb Common Stock and warrants to acquire 1,666,667 shares of New OmniAb Common Stock for an aggregate purchase price of $15,000,000, with such purchases to be consummated following the Domestication and prior to the Merger.

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Redemption Backstop. The Sponsor has agreed to purchase up to an additional 10,000,000 shares of New OmniAb Common Stock and up to an additional 1,666,667 New OmniAb Warrants, for an aggregate additional purchase price of up to $100,000,000, in order to backstop shareholder redemptions to the extent such redemptions would result in the cash proceeds to be available to the combined company following the Business Combination from APAC’s trust account to be less than $100,000,000.

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Merger. Following the above steps, Merger Sub will merge with and into OmniAb, with OmniAb continuing as the surviving company in the Merger and a wholly-owned subsidiary of New OmniAb. As a result of the Merger, the existing shares of OmniAb common stock will automatically convert into the right to receive shares of New OmniAb Common Stock.

New OmniAb, which will be the parent entity of OmniAb after the Merger, will be renamed to “OmniAb, Inc.,” effective as of the consummation of the Domestication (and after OmniAb has changed its name to “OmniAb Operations, Inc.”). New OmniAb Common Stock will be listed on Nasdaq under the trading symbol “OABI.”

What is a Reverse Morris Trust transaction?

A Reverse Morris Trust transaction allows a parent company (in this case, Ligand) to distribute all of the stock of a subsidiary (in this case, OmniAb) and combine it with an acquirer (in this case, APAC). The first step of such a transaction is a distribution of the subsidiary’s stock to the parent company stockholders (in this case, Ligand’s distribution of the stock of OmniAb to the Ligand stockholders in the Distribution) in a transaction that is generally tax-free under Section 355 of the Internal Revenue Code of 1986, as amended (the “Code”). The distributed subsidiary then combines with a third party (in this case, APAC through the Merger) in a reorganization that is generally tax-free under Section 368 of the Code. Such a transaction can qualify as generally tax-free for U.S. federal income tax purposes for the parent company and its stockholders if the transaction structure meets all applicable requirements, including that the parent company stockholders own more than 50% of the stock of the combined entity immediately after the combination.

For information about the material U.S. federal income tax consequences of the Distribution and the Merger that are relevant to Ligand stockholders, see “Material U.S. Federal Income Tax Consequences to Ligand Stockholders of the Distribution and Merger.”

What will happen in the Separation?

Ligand and certain of Ligand’s subsidiaries will engage in a series of transactions so that Ligand’s OmniAb Business is held by OmniAb and its subsidiaries and is separated from the remainder of Ligand’s businesses. See “Shareholder Proposal No. 1 — The Business Combination Proposal — Summary of the Separation Agreement.”

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What will happen in the Distribution?

After the Separation, Ligand will distribute to its stockholders all of the issued and outstanding shares of OmniAb Common Stock held by Ligand by way of a pro rata distribution.

Ligand will effect the Distribution by way of a spin-off. In a spin-off, the Ligand Board will establish a record date and a distribution date. Each share of Ligand Common Stock outstanding as of the Ligand Record Date for the Distribution will entitle its holder to receive one share of OmniAb Common Stock. Based on approximately 16,875,851 shares of Ligand Common Stock outstanding as of June 30, 2022 and applying the Distribution ratio of 1:1, OmniAb expects that a total of approximately 16,875,851 shares of OmniAb Common Stock will be distributed to Ligand stockholders and no shares of OmniAb Common Stock will continue to be owned by Ligand. The Distribution will be effected by Ligand delivering to the distribution agent a book-entry authorization representing the shares of OmniAb Common Stock being distributed in the Distribution for the account of Ligand’s stockholders. The distribution agent will hold such book-entry shares for the account of OmniAb’s stockholders (as of immediately after consummation of the Distribution) pending the Merger. The shares of OmniAb Common Stock will not be transferrable prior to the exchange of such shares for the shares of New OmniAb Common Stock pursuant to the Merger. See “The Separation and Distribution.”

What will happen in the Merger?

Immediately following the Distribution, OmniAb and Merger Sub will engage in a reverse triangular merger, in which Merger Sub will merge with and into OmniAb, with OmniAb surviving as a direct, wholly-owned subsidiary of APAC. In the Merger, each share of OmniAb Common Stock will be automatically converted into the right to receive shares of New OmniAb Common Stock. The number of shares of New OmniAb Common Stock to be received for each share of OmniAb Common Stock will be based on the calculation of the Base Exchange Ratio, the determination of which includes the relative trading values of the Ligand Common Stock in the “regular way” and “ex-distribution” markets during the five-trading-day period prior to the Closing. As such, the total number of shares of New OmniAb Common Stock to be received by OmniAb’s (Ligand’s) stockholders and the Base Exchange Ratio are not determinable until the Closing. However, for illustrative purposes, based on an assumed trading price of Ligand Common Stock of $89.22 per share (the closing price of the Ligand Common Stock on June 30, 2022) and the number of shares of Ligand Common Stock and equity awards outstanding as of June 30, 2022, and an assumed trading price of Ligand Common Stock in the “regular way” and “ex-distribution” trading markets of $89.22 and $40.20 per share, each respectively, each share of OmniAb Common Stock would be exchanged for approximately 4.9 shares of New OmniAb Common Stock and there would be an aggregate of 97,731,592 shares of New OmniAb Common Stock (inclusive of the Earnout Shares) received by OmniAb’s (Ligand’s) stockholders in the Merger.

Will the Distribution and the Merger occur on the same day?

Yes, the Merger will occur on the same day and immediately following the Distribution.

Who will serve on the New OmniAb Board following the Closing?

The Merger Agreement provides that, as of the Closing, the New OmniAb Board will consist of seven (7) members:

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John L. Higgins;

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Sarah Boyce;

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Jennifer Cochran, Ph.D.;

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Sunil Patel;

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Carolyn Bertozzi, Ph.D.;

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Matthew W. Foehr; and

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Joshua Tamaroff.

See “Management of New OmniAb after the Business Combination.”

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Who will manage New OmniAb after the Closing?

The Merger Agreement provides that, as of the Closing:

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Matthew W. Foehr, the current Chief Operating Officer of Ligand, will become President and Chief Executive Officer of New OmniAb;

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Kurt Gustafson will become Executive Vice President, Finance and Chief Financial Officer of New OmniAb; and

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Charles S. Berkman, the current Senior Vice President, General Counsel and Secretary of Ligand, will become Chief Legal Officer and Secretary of New OmniAb.

Is the completion of the Merger subject to any conditions?

Yes. The respective obligations of each party to effect the Closing of the Business Combination are subject to the fulfillment (or, to the extent permitted by applicable law, waiver) of certain conditions specified in the Merger Agreement.

The Merger Agreement provides that the obligations of the parties to consummate the Merger are conditioned on, among other things, (i) the expiration or termination of the waiting period under the HSR Act, (ii) receipt of required consents and approvals from certain governmental authorities, (iii) no agreement between Ligand or APAC and any governmental authority pursuant to which Ligand or APAC has agreed not to consummate the Business Combination shall be in effect, (iv) no governmental authority of competent jurisdiction shall have enacted or issued any law (whether temporary, preliminary or permanent), in each case that is in effect and which has the effect of restraining, enjoining or prohibiting the consummation of the transaction, (v) APAC shall have at least $5,000,001 of net tangible assets as of the Closing, (vi) the New OmniAb Common Stock issuable pursuant to the Business Combination shall have been approved for listing on Nasdaq, subject to official notice of issuance, (vii) Ligand, OmniAb, APAC and Merger Sub shall each have performed and complied in all material respects with the obligations, covenants and agreements required by the Merger Agreement to be performed or complied with by it at or prior the Effective Time, (viii) customary bring down conditions related to the accuracy of the parties’ respective representations and warranties in the Merger Agreement, (ix) the consummation of the Separation, the Distribution and the other transactions contemplated by the Separation Agreement, (x) each of APAC’s and OmniAb’s registration statements to be filed with the United States Securities and Exchange Commission shall have become effective, (xi) APAC’s shareholder approval of the Condition Precedent Proposals shall have been obtained and (xii) the receipt by Ligand and APAC of certain tax opinions. In addition, the respective obligations of OmniAb and Ligand to consummate the Business Combination is conditioned upon, among other items, the completion of the Forward Purchase and the Redemption Backstop, the resignation of all directors and all executive officers of APAC and the occurrence of the Domestication. APAC’s obligation to consummate the Business Combination is also conditioned on there having been no “Material Adverse Effect” on OmniAb since the date of the Merger Agreement.

Certain of the foregoing conditions, including the conditions in the Merger Agreement related to the receipt by Ligand and APAC of certain tax opinions, may be waived by the applicable party or parties in writing. To the extent that the APAC Board or the Ligand Board determines that any modifications by the parties, including any waivers of any conditions to the Closing, materially change the terms of the Business Combination, APAC and Ligand will notify their respective stockholders in a manner reasonably calculated to inform them about the modifications as may be required by law, by publishing a press release, and/or filing a current report on Form 8-K and by circulating a supplement to this proxy statement/prospectus/information statement to resolicit the votes of APAC shareholders, if required; if the change in terms includes the waiver of receipt of one or more tax opinions and the change in tax consequences is material, APAC will circulate a supplement and resolicit the votes of the APAC shareholders. For more information about conditions to the consummation of the Business Combination, see “Shareholder Proposal No. 1 — The Business Combination Proposal — Summary of the Merger Agreement — Conditions to Closing.”

Has Ligand set the Ligand Record Date for the Distribution?

No. Ligand will publicly announce the Ligand Record Date for the Distribution when it has been determined. This announcement will be made prior to the completion of the Separation, the Distribution and the Merger.

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Q: What do Ligand stockholders need to do to participate in the Distribution?

Ligand stockholders as of the Ligand Record Date are not required to take any action to receive OmniAb Common Stock in the Distribution, but they are urged to read this entire proxy statement/prospectus/information statement carefully. No Ligand stockholder approval of the Distribution is required, and Ligand stockholders are not being asked for a proxy. Ligand stockholders also do not need to pay any consideration, exchange or surrender their existing shares of Ligand Common Stock or take any other action to receive the shares of OmniAb Common Stock to which they are entitled. The Distribution will not affect the number of outstanding shares of Ligand Common Stock or any rights of Ligand stockholders, although it will affect the market value of each outstanding share of Ligand Common Stock.

What are holders of the Ligand Convertible Notes entitled to in the Distribution?

Holders of the Ligand Convertible Notes are not entitled to participate in the Distribution solely by virtue of their holding these notes. Such holders will participate only if they have exercised their conversion rights under their notes and received Ligand Common Stock prior to the Ligand Record Date for the Distribution. If holders of the Ligand Convertible Notes have exercised their conversion rights and received Ligand Common Stock prior to the Ligand Record Date for the Distribution, they will be entitled to participate in the Distribution in the same manner as any other holder of Ligand Common Stock. For a more detailed description, see “The Separation and Distribution.”

How will shares of New OmniAb Common Stock be issued?

Ligand stockholders will receive shares of New OmniAb Common Stock through the same or substantially similar channels that they currently use to hold or trade Ligand Common Stock (whether through a brokerage account, 401(k) plan or other channel). Receipt of shares of New OmniAb Common Stock will be documented for Ligand stockholders in substantially the same manner that stockholders typically receive stockholder updates, such as monthly broker statements and 401(k) statements.

The Distribution of OmniAb Common Stock will be effected by Ligand delivering to the distribution agent, Computershare Trust Company, N.A. (“Computershare”), a book-entry authorization representing the shares of OmniAb Common Stock being distributed in the Distribution for the account of Ligand’s stockholders. The distribution agent will hold such book-entry shares for the account of OmniAb’s stockholders (as of immediately after consummation of the Distribution) pending the Merger. The shares of OmniAb Common Stock will not be transferrable prior to the exchange of such shares for the shares of New OmniAb Common Stock pursuant to the Merger. See “The Separation and Distribution.” Immediately thereafter, as a result of and upon the Closing of the Merger, each outstanding share of OmniAb Common Stock (other than Treasury Shares) will be cancelled in exchange for the right to receive a number of shares of New OmniAb Common Stock equal to the Base Exchange Ratio, and a number of OmniAb Earnout Shares equal to the Earnout Exchange Ratio. Computershare, as exchange agent, will electronically distribute shares of New OmniAb Common Stock and OmniAb Earnout Shares to holders of Ligand Common Stock on the Ligand Record Date or to the stockholders brokerage firm on the stockholders’ behalf by way of direct registration in book-entry form. Computershare will mail the stockholders a book-entry account statement that reflects their shares of New OmniAb Common Stock and OmniAb Earnout Shares, or the stockholders’ bank or brokerage firm will credit their account for such shares. OmniAb Earnout Shares may not be transferred until the applicable OmniAb Triggering Event has occurred. See “Shareholder Proposal No. 1 — The Business Combination Proposal — Summary of the Merger Agreement — Merger Consideration.”

What will happen to the listing of Ligand Common Stock?

After the Distribution, Ligand Common Stock will continue to trade on Nasdaq under the symbol “LGND.” Holders of Ligand Common Stock will retain all their shares of Ligand Common Stock.

Will the Distribution affect the market price of shares of Ligand Common Stock?

Yes. As a result of the Distribution, Ligand expects the trading price of shares of Ligand Common

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Stock immediately following the Distribution to be lower than the “regular way” trading price of such shares immediately prior to the Distribution because the trading price will no longer reflect the value of the OmniAb Business. There can be no assurance that the aggregate market value of the Ligand Common Stock plus the pro rata portion of Aggregate Merger Consideration a Ligand stockholder is entitled to in the Merger, including the aggregate market value of New OmniAb Common Stock following the Distribution and Merger, will be higher or lower than the market value of Ligand Common Stock if the Distribution and Merger did not occur.

Will Ligand shareholders who sell their shares of Ligand Common Stock shortly before the completion of the Distribution and Merger still be entitled to receive shares of OmniAb Common Stock with respect to the ordinary shares of Ligand that were sold?

Ligand Common Stock is currently listed on Nasdaq under the ticker symbol “LGND.” It is currently expected that beginning not earlier than one business day before the Ligand Record Date to be established for the Distribution, and continuing through the Closing, there will be two markets in Ligand Common Stock on Nasdaq: a “regular way” market and an “ex-distribution” market.

•

If a Ligand shareholder sells Ligand Common Stock in the “regular way” market under the symbol “LGND” during this time period, that Ligand shareholder will be selling both his or her shares of Ligand Common Stock and the right to receive shares of OmniAb Common Stock that will be converted into shares of New OmniAb Common Stock, and cash in lieu of fractional shares (if any), at the Closing. Ligand shareholders should consult their brokers before selling their ordinary shares of Ligand in the “regular way” market during this time period to be sure they understand the effect of the Nasdaq “due-bill” procedures.

•

If a Ligand shareholder sells Ligand Common Stock in the “ex-distribution” market during this time period, that Ligand shareholder will be selling only his or her Ligand Common Stock, and will retain the right to receive shares of OmniAb Common Stock that will be converted into shares of New OmniAb Common Stock, and cash in lieu of fractional shares (if any), at the Closing.

After the Closing, Ligand Common Stock will no longer trade in the “ex-distribution” market, and Ligand Common Stock that is sold in the “regular way” market will no longer reflect the right to receive shares of OmniAb Common Stock that will be converted into shares of New OmniAb Common Stock, and cash in lieu of fractional shares (if any), at the Closing. The receipt of cash in lieu of fractional shares generally will be taxable to the recipient stockholders for U.S. federal income tax purposes as described in “Material U.S. Federal Income Tax Consequences to Ligand Stockholders of the Distribution and Merger.”

What are the material U.S. federal income tax consequences to Ligand stockholders resulting from the Distribution and the Merger?

Ligand stockholders are not expected to recognize any gain or loss as a result of the Distribution and the Merger, except for any gain or loss attributable to the receipt of cash in lieu of a fractional shares of stock pursuant to the Distribution or Merger. The material U.S. federal income tax consequences of the Distribution and the Merger that are relevant to Ligand stockholders are described in more detail under “Material U.S. Federal Income Tax Consequences to Ligand Stockholders of the Distribution and Merger.” Ligand shareholders should consult their own tax advisors for a full understanding of the tax consequences to them of the Distribution and the Merger.

What are the material U.S. federal income tax consequences to APAC shareholders resulting from the Distribution and the Merger?

APAC shareholders are not expected to recognize any gain or loss as a result of the Distribution or the Merger. APAC shareholders should consult their own tax advisors for a full understanding of the tax consequences of the Distribution and the Merger. The material U.S. federal income tax consequences of the Business Combination to APAC shareholders are described under “Material U.S. Federal Income Tax Consequences to APAC Shareholders.”

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Does Ligand have to pay anything to APAC if the Merger Agreement is terminated?

In the event that the Merger Agreement is terminated by Ligand in connection with its entering into a definitive agreement in respect of a Ligand Acquisition Proposal, concurrently with such termination, Ligand shall be obligated to pay APAC a termination fee of (i) if terminated within 60 days of the date of the Merger Agreement, $40,000,000, (ii) if terminated between 61 and 120 days after the date of the Merger Agreement, $50,000,000, and (iii) if terminated between 121 and 180 days after the date of the Merger Agreement, $70,000,000 (each such amount, the “Termination Fee”), by wire transfer of immediately available funds to an account designated by APAC in writing, and, in addition to payment of the Termination Fee, Ligand also shall pay the APAC Expenses (the “APAC Expenses Reimbursement”) by wire transfer of immediately available funds to an account designated by APAC in writing no later than two business days after the date on which APAC delivers to Ligand a written invoice for the APAC Expenses. As used in this subsection, “APAC Expenses” means the amount of all reasonable and documented out-of-pocket fees and expenses, but not to exceed $7,500,000, incurred or paid by APAC and its affiliates in connection with the Merger Agreement and the Business Combination, including fees and expenses of law firms, accounting firms, financial advisors, outside experts and consultants. For a discussion of the circumstances under which Ligand may have to pay a termination fee, see “Shareholder Proposal No. 1 — The Business Combination Proposal — Summary of the Merger Agreement — Termination Fees and Expenses Payable in Certain Circumstances.” The A&R FPA also provides that in the event the Merger Agreement is terminated by Ligand under circumstances in which the Termination Fee would be payable under the Merger Agreement, Ligand shall pay the Sponsor a termination fee of $12,500,000 in connection therewith. The A&R FPA is attached to this proxy statement/prospectus/information statement as Annex D.

What proposals are shareholders of APAC being asked to vote upon?

At the extraordinary general meeting, APAC is asking holders of ordinary shares to consider and vote upon:

•

a proposal to approve by special resolution and adopt (i) the Merger Agreement, (ii) the Transaction Documents and (iii) each of the transactions contemplated thereby, in each case, in accordance with the terms and subject to the conditions set forth in the Merger Agreement and such Transaction Documents, as more fully described elsewhere in this proxy statement/prospectus/information statement;

•

a proposal to adopt and approve by special resolution the Domestication and change in the jurisdiction of incorporation of APAC from the Cayman Islands to the State of Delaware;

•

a proposal to approve by special resolution and adopt the Proposed Certificate of Incorporation and the Proposed Bylaws of APAC in connection with the Domestication, and the change of its name from APAC to OmniAb, Inc.;

•

proposals to approve, on a non-binding advisory basis, certain material differences between APAC’s Amended and Restated Memorandum and Articles of Association and the Proposed Certificate of Incorporation and Proposed Bylaws;

•

a proposal to approve by ordinary resolution the election of seven directors to serve staggered terms, who, upon consummation of the Merger, will be the directors of New OmniAb;

•

a proposal to approve by ordinary resolution the OmniAb, Inc. 2022 Incentive Award Plan as described by the Employee Matters Agreement;

•

a proposal to approve by ordinary resolution the OmniAb, Inc. 2022 Employee Stock Purchase Plan as described by the Employee Matters Agreement; and

•

a proposal to approve the adjournment of the extraordinary general meeting to a later date or dates, if necessary, to permit further solicitation and vote of proxies in the event that there are insufficient votes present to constitute a quorum or for the approval of one or more proposals at the extraordinary general meeting.

If APAC’s shareholders do not approve each of the Condition Precedent Proposals, then unless certain conditions in the Merger Agreement are waived by the applicable parties to the Merger Agreement, the

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Merger Agreement could terminate and the Business Combination may not be consummated. See “Shareholder Proposal No. 1 — The Business Combination Proposal,” “Shareholder Proposal No. 2 — The Domestication Proposal,” “Shareholder Proposal No. 3 — The Organizational Documents Proposal,” “Shareholder Proposal No. 4 — The Non-Binding Governance Proposals,” “Shareholder Proposal No. 5 — The Stock Issuance Proposal,” “Shareholder Proposal No. 6 — The Incentive Plan Proposal,” “Shareholder Proposal No. 7 — The ESPP Proposal,” “Shareholder Proposal No. 8 — The Director Election Proposal” and “Shareholder Proposal No. 9 — The Adjournment Proposal.”

APAC will hold the extraordinary general meeting to consider and vote upon these proposals. This proxy statement/prospectus/information statement contains important information about the Business Combination and the other matters to be acted upon at the extraordinary general meeting. Shareholders of APAC should read it carefully.

After careful consideration, the APAC Board has determined that the Business Combination Proposal, the Domestication Proposal, the Organizational Documents Proposal, the Non-Binding Governance Proposals, the Director Election Proposal, the Stock Issuance Proposal, the Incentive Plan Proposal, the ESPP Proposal and the Adjournment Proposal are in the best interests of APAC and its shareholders and unanimously recommends that you vote or give instruction to vote “FOR” each of those proposals.

The existence of financial and personal interests of one or more of APAC’s directors may result in a conflict of interest on the part of such director(s) between what he, she or they may believe is in the best interests of APAC and its shareholders and what he, she or they may believe is best for himself, herself or themselves in determining to recommend that shareholders vote for the proposals. In addition, APAC’s officers have interests in the Business Combination that may conflict with your interests as a shareholder. See the section entitled “Shareholder Proposal No. 1 — The Business Combination Proposal — Interests of APAC’s Directors and Executive Officers in the Business Combination” for a further discussion of these considerations.

Are the proposals conditioned on one another?

Yes. Each of the Condition Precedent Proposals is cross-conditioned on the approval of the others. The Adjournment Proposal is not conditioned upon the approval of any other proposal set forth in this proxy statement/prospectus/information statement. The Non-Binding Governance Proposals are comprised of non-binding advisory proposals.

Why is APAC proposing the Business Combination?

APAC was incorporated to effect a merger, share exchange, asset acquisition, share purchase, reorganization or similar business combination, with one or more businesses or entities.

Based on our due diligence investigations of OmniAb, the management of OmniAb and the industry in which it operates, including the financial and other information provided by OmniAb in the course of these due diligence investigations, the APAC Board believes that the Business Combination with OmniAb is in the best interests of APAC and its shareholders and presents an opportunity to increase shareholder value. However, there is no assurance of this. See “Shareholder Proposal No. 1 — The Business Combination Proposal — The APAC Board’s Reasons for the Business Combination” for additional information.

Although the APAC Board believes that the Business Combination with OmniAb presents an attractive business combination opportunity and is in the best interests of APAC and its shareholders, the APAC Board did consider certain potentially material negative factors in arriving at that conclusion, including, among others, limitations on New OmniAb’s business activities for a two-year period following the closing of the Business Combination with respect to its ability to divest, dissolve or liquidate its businesses and assets, enter into stock purchase or buyback programs or issue stock. These factors are discussed in greater detail in the section entitled “Shareholder Proposal No. 1 — The Business Combination Proposal — The APAC Boards’ Reasons for the Business Combination,” as well as in the sections entitled “Risk Factors.”

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What will OmniAb stockholders receive in return for APAC’s acquisition of all of the issued and outstanding equity interests of OmniAb?

Common Stock. As a result of and upon the Closing, among other things, each outstanding share of OmniAb Common Stock (other than Treasury Shares), will be cancelled upon the Effective Time in exchange for the right to receive a number of shares of New OmniAb Common Stock equal to the Base Exchange Ratio.

Earnout Shares. In addition, as a result of and upon the Closing, among other things, each outstanding share of OmniAb Common Stock (other than Treasury Shares), will be cancelled upon the Effective Time in exchange for the right to receive a number of OmniAb Earnout Shares equal to the Earnout Exchange Ratio. Holders of OmniAb Common Stock and OmniAb Equity Awards will receive earnout consideration in the form of an additional 15,000,000 OmniAb Earnout Shares, all of which will be automatically forfeited for no consideration if an applicable OmniAb Triggering Event has not occurred with respect to such OmniAb Earnout Shares during the period from the date of the Closing to and including the fifth anniversary of the date of the Closing.

Total Consideration. The total number of shares of New OmniAb Common Stock to be received by OmniAb’s stockholders or reserved for issuance pursuant to the New OmniAb Equity Awards into which OmniAb Equity Awards are to be converted (other than, for purposes of this calculation, Out-of-the-Money OmniAb Options) will be equal to the Aggregate Merger Consideration. In addition to the Aggregate Merger Consideration, holders of OmniAb Common Stock and OmniAb Equity Awards will also receive earnout consideration in the form of the OmniAb Earnout Shares.

Equity Awards. In addition, all (i) OmniAb Options, (ii) OmniAb RSUs and (iii) OmniAb PSUs, in each case, that are outstanding as of immediately prior to the Effective Time, will be converted into such number of (a) New OmniAb Options, (b) New OmniAb RSUs and (c) New OmniAb PSUs, respectively, in each case, equal to (1) the number of shares of OmniAb Common Stock underlying such OmniAb Equity Awards immediately prior to the Effective Time multiplied by (2) the Base Exchange Ratio. Each holder of an OmniAb Option, OmniAb RSU and/or OmniAb PSU will also receive a number of OmniAb Earnout Shares equal to the number of shares of OmniAb Common Stock underlying such OmniAb Options, OmniAb RSUs and/or OmniAb PSUs, as applicable, multiplied by the Earnout Exchange Ratio, and the exercise price of each outstanding New OmniAb Option will be equal to the exercise price of the pre-conversion OmniAb Option divided by the Base Exchange Ratio. For further details, see “Shareholder Proposal No. 1 — The Business Combination Proposal — Consideration, Treatment of OmniAb Options, OmniAb RSUs and OmniAb PSUs.”

What equity stake will current APAC shareholders and OmniAb stockholders (after the Distribution) hold in New OmniAb immediately after the consummation of the Business Combination?

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OmniAb issues 97,731,592 shares of New OmniAb Common Stock to former stockholders of OmniAb and former holders of OmniAb Equity Awards as of immediately prior to the Effective Time and (c) that New OmniAb issues 1,500,000 shares of New OmniAb Common Stock to the Sponsor pursuant to the Forward Purchase, (ii) exclude all New OmniAb Options that may be exercisable for shares of New OmniAb Common Stock, New OmniAb RSUs and New OmniAb PSUs, (iii) include the Sponsor Earnout Shares and the OmniAb Earnout Shares and (iv) exclude the impact of any New OmniAb Warrants that will be outstanding following the Business Combination (we refer to this set of assumptions as the “no redemption scenario”). If the actual facts are different from the no redemption scenario, the percentage ownership of New OmniAb held by such constituencies will be different.

The following table illustrates varying ownership levels in New OmniAb immediately following the consummation of the Business Combination based on the no redemption scenario and, alternatively (i) based on the assumption that 11,500,000 APAC Class A Ordinary Shares are redeemed in connection with the Business Combination at approximately $10.27 per share (we refer to this set of assumptions as the “50% redemption scenario”) and (ii) based on the assumption that 23,000,000 APAC Class A Ordinary Shares are redeemed in connection with the Business Combination at approximately $10.27 per share, and the Sponsor funds $100,000,000 pursuant to the Redemption Backstop provided for in the A&R FPA (we refer to this set of assumptions as the “maximum redemption scenario”). Regardless of the extent of redemptions, the shares of New OmniAb Common Stock owned by non-redeeming shareholders will have an implied value of $10.27 per share immediately upon consummation of the Business Combination. The trading price of New OmniAb Common Stock immediately after consummation of the transaction is unpredictable. Please see “Risk Factors — Risks Related to Redemption” for additional information.

	Share Ownership in New OmniAb
	No Redemption Scenario				50% Redemption Scenario(1)				Maximum Redemption Scenario(2)
	Number of Shares		Percentage of Outstanding Shares		Number of Shares		Percentage of Outstanding Shares		Number of Shares		Percentage of Outstanding Shares
APAC’s public shareholders		23,000,000		18.0%		11,500,000		9.9%		—		0.0%
Sponsor and related parties(3)(4)(6)		7,250,000		5.7%		7,250,000		6.2%		17,250,000		15.0%
OmniAb’s (Ligand’s) stockholders(5)(6)		97,731,592		76.3%		97,731,592		83.9%		97,731,592		85.0%
Total(7)(8)		127,981,592		100.0%		116,481,592		100.0%		114,981,592		100.0%

(1)

Assumes redemptions of 11,500,000 APAC Class A Ordinary Shares in connection with the Business Combination.

(2)

Assumes redemptions of 23,000,000 APAC Class A Ordinary Shares in connection with the Business Combination.

(3)

Includes 5,750,000 Class B Ordinary Shares that will be converted in New OmniAb Common Stock. The Sponsor Earnout Shares were included in the pro forma capitalization as, during the Earnout Period, holders of the Sponsor Earnout Shares are entitled to vote such Sponsor Earnout Shares and receive dividends and other distribution in respect thereof, pursuant to the Sponsor Insider Agreement.

(4)

Pursuant to the A&R FPA, includes 1,500,000 shares of New OmniAb Common Stock purchased by the Sponsor in the Forward Purchase in the no redemption, 50% redemption and maximum redemption scenarios and 10,000,000 shares of New OmniAb Common Stock purchased by the Sponsor in the Redemption Backstop in the maximum redemption scenario.

(5)

Includes 15,000,000 OmniAb Earnout Shares issued to former OmniAb stockholders and former OmniAb Equity Award holders, entitled to exercise the voting rights carried by such Earnout Shares and receive any dividends or other distributions in respect of such OmniAb Earnout Shares, during the Earnout Period. For a description of the assumptions used in calculating the number of shares to be owned by OmniAb’s (Ligand’s) stockholders, see “Shareholder Proposal No. 1 — The Business Combination Proposal — Ownership of APAC after the Business Combination.”

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(6)

The table below sets forth the share ownership in New OmniAb assuming that the Sponsor Earnout Shares and the OmniAb Earnout Shares are forfeited according to their terms:

	Share Ownership in New OmniAb
	No Redemption Scenario				50% Redemption Scenario				Maximum Redemption Scenario
	Number of Shares		Percentage of Outstanding Shares		Number of Shares		Percentage of Outstanding Shares		Number of Shares		Percentage of Outstanding Shares
APAC’s public shareholders		23,000,000		20.7%		11,500,000		11.6%		—		0.0%
Sponsor and related parties		5,333,333		4.8%		5,333,333		5.4%		16,052,083		16.2%
OmniAb’s (Ligand’s) stockholders		82,731,592		74.5%		82,731,592		83.0%		82,731,592		83.8%
Total		111,064,925		100.0%		99,564,925		100.0%		98,783,675		100.0%

(7)

The table excludes the following:

•

13,587,254 unexercised OmniAb Options;

•

1,402,039 OmniAb RSUs and OmniAb PSUs;

•

7,666,667 unexercised APAC Public Warrants;

•

8,233,333 unexercised APAC Private Placement Warrants;

•

1,666,667 unexercised APAC Warrants issued in the Forward Purchase;

•

1,666,667 unexercised APAC Warrants issued in the Redemption Backstop in the maximum redemption scenario; and

•

500,000 unexercised APAC Private Placement Warrants issuable pursuant to the convertible promissory note.

(8)

If all of the Sponsor’s APAC Warrants are exercised, which include the 8,233,333 APAC Private Placement Warrants, the 1,666,667 APAC Warrants issued in the Forward Purchase and, the 1,666,667 APAC Warrants issued in the Redemption Backstop in the maximum redemption scenario, and the 500,000 unexercised APAC Private Placement Warrants issuable pursuant to the convertible promissory note, Sponsor would own: (1) approximately 12.8% of the shares of New OmniAb in the no redemption scenario, (2) approximately 13.9% of the shares of New OmniAb in the 50% redemption scenario or (3) approximately 23.1% of the shares of New OmniAb in the maximum redemption scenario.

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The sensitivity table below sets forth the potential additional dilutive impact of each of the APAC Warrants, the 2022 Plan, the ESPP, the OmniAb Options and the OmniAb RSUs and PSUs in each redemption scenario.

	Share Ownership in New OmniAb(1)
	No Redemptions Scenario				50% Redemptions Scenario				100% Redemptions Scenario
Additional Dilution Sources	Number of Underlying Shares		Percentage of then Outstanding Shares		Number of Underlying Shares		Percentage of then Outstanding Shares		Number of Underlying Shares		Percentage of then Outstanding Shares
APAC Warrants
APAC Public Warrants(2)		7,666,667		5.7%		7,666,667		6.2%		7,666,667		6.3%
APAC Private Placement Warrants(3)		8,233,333		6.0%		8,233,333		6.6%		8,233,333		6.7%
APAC Warrants issued in the Forward Purchase(4)		1,666,667		1.3%		1,666,667		1.4%		1,666,667		1.4%
APAC Warrants issued in the Redemption Backstop(5)		0		0.0%		0		0.0%		1,666,667		1.4%
APAC Private Placement Warrants Issuable Pursuant to Convertible Promissory Note(6)		500,000		0.4%		500,000		0.4%		500,000		0.4%
OmniAb Prior Plans
OmniAb Options(7)		13,587,254		9.6%		13,587,254		10.4%		13,587,254		10.6%
OmniAb RSUs and OmniAb PSUs(8)		1,402,039		1.1%		1,402,039		1.2%		1,402,039		1.2%
New OmniAb Proposed Plans
2022 Plan(9)		18,235,000		12.5%		16,625,000		12.5%		16,415,000		12.5%
ESPP(10)		1,953,750		1.5%		1,781,250		1.5%		1,758,750		1.5%
Total Additional Dilutive Sources(11)		53,244,710		29.4%		51,462,210		30.6%		52,896,377		31.5%

(1)

Percentages in this table assume that the dilutive shares are added to the outstanding shares in the respective redemption scenario.

(2)

This row assumes exercise of all APAC Public Warrants to purchase 7,666,667 shares of New OmniAb Common Stock. Percentages in this row represent (a) the shares of New OmniAb Common Stock underlying the APAC Public Warrants divided by (b) (i) the outstanding shares as of immediately following the Closing in the applicable redemption scenario plus (ii) 7,666,667 shares of New OmniAb Common Stock underlying the APAC Public Warrants.

(3)

This row assumes exercise of all APAC Private Placement Warrants to purchase 8,233,333 shares of New OmniAb Common Stock. Percentages in this row represent (a) the shares of New OmniAb Common Stock underlying the APAC Private Placement Warrants divided by (b) (i) the outstanding shares as of immediately following the Closing in the applicable redemption scenario plus (ii) 8,233,333 shares of New OmniAb Common Stock underlying the APAC Private Placement Warrants.

(4)

This row assumes exercise of all APAC Warrants issued in the Forward Purchase to purchase 1,666,667 shares of New OmniAb Common Stock. Percentages in this row represent (a) the shares of New OmniAb Common Stock underlying the APAC Warrants issued in the Forward Purchase divided by (b) (i) the outstanding shares as of immediately following the Closing in the applicable redemption scenario plus (ii) 1,666,667 shares of New OmniAb Common Stock underlying the APAC Warrants issued in the Forward Purchase.

(5)

This row assumes (solely in the case of the maximum redemption scenario) exercise of all APAC

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Warrants issued in the Redemption Backstop to purchase 1,666,667 shares of New OmniAb Common Stock. Percentages in this row represent (a) the shares of New OmniAb Common Stock underlying the APAC Warrants purchased in the Redemption Backstop divided by (b) (i) the outstanding shares as of immediately following the Closing in the applicable redemption scenario plus (ii) 1,666,667 shares of New OmniAb Common Stock underlying the APAC Warrants purchased in the Redemption Backstop (in the maximum redemption scenario).

(6)

This row assumes exercise of all 500,000 APAC Warrants to purchase New OmniAb Common Stock issuable pursuant to the repayment of the convertible promissory note. Percentages in this row represent (a) the shares of New OmniAb Common Stock underlying the APAC Warrants issuable pursuant to the repayment of the convertible promissory note divided by (b) (i) the outstanding shares as of immediately following the Closing in the applicable redemption scenario plus (ii) 500,000 shares of New OmniAb Common Stock underlying the APAC Warrants issuable pursuant to the repayment of the convertible promissory note.

(7)

This row assumes the exercise of all 13,587,254 OmniAb Options. Percentages in this row represent (a) the shares of New OmniAb Common Stock underlying the OmniAb Options divided by (b) (i) the outstanding shares as of immediately following the Closing in the applicable redemption scenario plus (ii) 13,587,254 shares of New OmniAb Common Stock underlying the OmniAb Options. For a description of the assumptions used in calculating the number of OmniAb Options, see “Shareholder Proposal No. 1 — The Business Combination Proposal — Ownership of APAC after the Business Combination.”

(8)

This row assumes vesting of all 1,402,039 OmniAb RSUs and OmniAb PSUs. Percentages in this row represent (a) the shares of New OmniAb Common Stock underlying the OmniAb RSUs and OmniAb PSUs divided by (b) (i) the outstanding shares as of immediately following the Closing in the applicable redemption scenario plus (ii) 1,402,039 shares of New OmniAb Common Stock underlying the OmniAb RSUs and OmniAb PSUs. For a description of the assumptions used in calculating the number of OmniAb RSUs and OmniAb PSUs, see “Shareholder Proposal No. 1 — The Business Combination Proposal — Ownership of APAC after the Business Combination.”

(9)

This row assumes the issuance of a number of shares equal to 14% of the fully diluted shares of New OmniAb Common Stock (calculated as specifically provided under the 2022 Plan) to be outstanding immediately following the Closing reserved for issuance under the 2022 Plan. Percentages in this row represent (a) the shares of New OmniAb Common Stock reserved and issuable under the 2022 Plan divided by (b) the sum of (i) the outstanding shares as of immediately following the Closing in the applicable redemption scenario and (ii) the shares of New OmniAb Common Stock reserved and issuable under the 2022 Plan. For a description of the assumptions used in calculating the number of shares reserved under the proposed 2022 Plan, see “Shareholder Proposal No. 6 — Incentive Plan Proposal.”

(10)

This row assumes the issuance of a number of shares equal to 1.5% of the fully diluted shares of New OmniAb Common Stock (calculated as specifically provided under the ESPP) to be outstanding immediately following the Closing reserved for issuance under the ESPP. Percentages in this row represent (a) the shares of New OmniAb Common Stock reserved and issuable under the ESPP divided by (b) the sum of (i) the outstanding shares as of immediately following the Closing in the applicable redemption scenario and (ii) the shares of New OmniAb Common Stock reserved and issuable under the ESPP. For a description of the assumptions used in calculating the number of shares reserved under the proposed ESPP, see “Shareholder Proposal No. 7 — ESPP Proposal.”

(11)

This row assumes the exercise and vesting of all awards and warrants listed in the rows above. Percentages in this row represent (a) the shares of New OmniAb Common Stock underlying all awards and warrants listed in the rows above divided by (b) (i) the outstanding shares as of immediately following the Closing in the applicable redemption scenario plus (ii) all shares of New OmniAb Common Stock underlying the awards and warrants listed in the rows above.

In addition to the changes in percentage ownership depicted above, variation in the levels of redemption will impact the dilutive effect of certain equity issuances related to the Business Combination. As illustrated in the table below, certain equity issuances may have a dilutive effect on the per share value of New OmniAb. See the section entitled “Risk Factors — Risks Related to Redemption” for additional information.

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	Share Ownership in New OmniAb
	No Redemptions Scenario					50% Redemptions Scenario(1)					100% Redemptions Scenario(2)
	Number of Shares		Value per Share(3)			Number of Shares		Value per Share(3)			Number of Shares		Value per Share(3)
Base Scenario(4)		127,981,592		$	10.27		116,481,592		$	10.27		114,981,592		$	10.25
Excluding Sponsor Earnout Shares and OmniAb Earnout Shares(5)		111,064,925		$	11.83		99,564,925		$	12.01		98,783,675		$	11.93
Assuming Exercise of APAC Public Warrants(6)		135,648,259		$	10.34		124,148,259		$	10.35		122,648,259		$	10.32
Assuming Exercise of APAC Private Placement Warrants(7)		136,214,925		$	10.34		124,714,925		$	10.35		123,214,925		$	10.33
Assuming Exercise of APAC Warrants issued in the Forward Purchase (8)		129,648,259		$	10.29		118,148,259		$	10.29		116,648,259		$	10.26
Assuming Exercise of APAC Warrants issued in the Redemption Backstop(9)		127,981,592		$	10.27		116,481,592		$	10.27		116,648,259		$	10.26
Assuming Exercise of APAC Private Placement Warrants Issuable Pursuant to Convertible Promissory Note(10)		128,481,592		$	10.27		116,981,592		$	10.28		115,481,592		$	10.25
Including Conversion of OmniAb RSUs and OmniAb PSUs(11)		129,383,631		$	10.16		117,883,631		$	10.15		116,383,631		$	10.12
Including shares reserved for issuance under 2022 Plan(12)		146,216,592		$	8.99		133,106,592		$	8.99		131,396,592		$	8.97
Including shares reserved for issuance under ESPP(13)		129,935,342		$	10.25		118,262,842		$	10.25		116,740,342		$	10.22

(1)

Assumes redemptions of 11,500,000 APAC Class A Ordinary Shares in connection with the Business Combination.

(2)

Assumes redemptions of 23,000,000 APAC Class A Ordinary Shares in connection with the Business Combination.

(3)

Based on a post-transaction equity value of New OmniAb of the following (in billions):

	No Redemptions Scenario			50% Redemptions Scenario			100% Redemptions Scenario
	Post- Transaction Equity Value			Post- Transaction Equity Value			Post- Transaction Equity Value
Base Scenario		$	1.31		$	1.20(3)(a)		$	1.18(3)(b)
Excluding Sponsor Earnout Shares and OmniAb Earnout Shares(3)(c)		$	1.31		$	1.20		$	1.18
Assuming Exercise of APAC Public Warrants(3)(d)		$	1.40		$	1.28		$	1.27
Assuming Exercise of APAC Private Placement Warrants(3)(e)		$	1.41		$	1.29		$	1.27
Assuming Exercise of APAC Warrants issued in the Forward Purchase(3)(f)		$	1.33		$	1.22		$	1.20
Assuming Exercise of APAC Warrants issued in the Redemption Backstop(3)(g)		$	1.31		$	1.20		$	1.20
Assuming Exercise of APAC Private Placement Warrants Issuable Pursuant to Convertible Promissory Note(3)(h)		$	1.32		$	1.20		$	1.18
Including Conversion of OmniAb RSUs and OmniAb PSUs(3)(i)		$	1.31		$	1.20		$	1.18

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	No Redemptions Scenario			50% Redemptions Scenario			100% Redemptions Scenario
	Post- Transaction Equity Value			Post- Transaction Equity Value			Post- Transaction Equity Value
Including shares reserved for issuance under 2022 Plan(3)(j)		$	1.31		$	1.20		$	1.18
Including shares reserved for issuance under ESPP(3)(k)		$	1.33		$	1.21		$	1.19

(3)(a)

Based on a post-transaction equity value of New OmniAb of approximately $1.20 billion, or approximately $1.31 billion less the approximately $118.1 million (or $10.27 per share, representing its per share portion of the principal in the trust account) that would be paid from the trust account to redeem 11,500,000 public shares in connection with the Business Combination.

(3)(b)

Based on a post-transaction equity value of New OmniAb of approximately $1.18 billion, or approximately $1.31 billion less the approximately $236.2 million (or $10.27 per share, representing its per share portion of the principal in the trust account) that would be paid from the trust account to redeem 23,000,000 public shares in connection with the Business Combination, plus the $100.0 million that would be received from the issuance of 10,000,000 shares at $10.00 per share pursuant to the Redemption Backstop.

(3)(c)

Based on a post-transaction equity value of New OmniAb at the Base Scenario in the respective redemption scenario column, but excluding (i) the 15,000,000 OmniAb Earnout Shares that holders of OmniAb Common Stock and OmniAb Equity Awards will receive at the Closing and (ii) the 1,916,667 Sponsor Earnout Shares Shares in the no redemption scenario and the 50% redemption scenario, or 1,197,917 Sponsor Earnout Shares in the max redemption scenario.

(3)(d)

Based on a post-transaction equity value of New OmniAb at the Base Scenario in the respective redemption scenario column plus the full exercise of the APAC Public Warrants for a total cash exercise price of approximately $88.2 million (or $11.50 per share).

(3)(e)

Based on a post-transaction equity value of New OmniAb at the Base Scenario in the respective redemption scenario column plus the full exercise of the APAC Private Placement Warrants for a total cash exercise price of approximately $94.7 million (or $11.50 per share).

(3)(f)

Based on a post-transaction equity value of New OmniAb at the Base Scenario in the respective redemption scenario column plus the full exercise of the APAC Warrants issued in connection with the Forward Purchase for a total cash exercise price of approximately $19.2 million (or $11.50 per share).

(3)(g)

Based on a post-transaction equity value of New OmniAb at the Base Scenario in the respective redemption scenario column plus the full exercise of the APAC Warrants issued in connection with the Redemption Backstop for a total cash exercise price of approximately $19.2 million (or $11.50 per share) (only in the maximum redemption scenario).

(3)(h)

Based on a post-transaction equity value of New OmniAb at the Base Scenario in the respective redemption scenario column plus the full exercise of the APAC Warrants issuable in connection with the convertible promissory note for a total cash exercise price of approximately $5.8 million (or $11.50 per share).

(3)(i)

Based on a post-transaction equity value of New OmniAb at the Base Scenario in the respective redemption scenario column, but including the 1,402,039 OmniAb RSUs and OmniAb PSUs.

(3)(j)

Based on a post-transaction equity value of New OmniAb at the Base Scenario in the respective redemption scenario column, but including the shares reserved and issuable under the 2022 Plan.

(3)(k)

Based on a post-transaction equity value of New OmniAb at the Base Scenario in the respective redemption scenario column plus the value of the aggregate share reserves issuable under the ESPP for an aggregate purchase price of approximately $17.1 million, $15.5 million and $15.4 million for the no redemption scenario, the 50% redemption scenario and the maximum

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redemption scenario, respectively (representing, per share, 85% of the implied value of New OmniAb Common Stock ($10.27), or approximately $8.73 per share).

(4)

Represents (a) the 82,731,592 of New OmniAb Common Stock issued to Ligand stockholders at the Closing, pursuant to the Business Combination, (b) the 15,000,000 OmniAb Earnout Shares that holders of OmniAb Common Stock and OmniAb Equity Awards will receive at the Closing, (c) the 23,000,000 APAC Class A Ordinary Shares that will be converted into shares of New OmniAb Common Stock in the Domestication, (d) the 5,750,000 Class B Ordinary Shares that will be converted into shares of New OmniAb Common Stock in the Domestication, (e) the 1,500,000 shares of New OmniAb Common Stock issued to the Sponsor pursuant to the A&R FPA and (f) the 10,000,000 shares issued to the Sponsor pursuant to the Redemption Backstop in the maximum redemption scenario, less any shares that are redeemed, as described above.

(5)

Represents the Base Scenario less (i) the 15,000,000 OmniAb Earnout Shares and (ii) the 1,916,667 Sponsor Earnout Shares in the no redemption scenario and the 50% redemption scenario, or 1,197,917 Sponsor Earnout Shares in the max redemption scenario.

(6)

Represents the Base Scenario plus 7,666,667 shares of New OmniAb Common Stock issuable upon the exercise of the APAC Public Warrants.

(7)

Represents the Base Scenario plus 8,233,333 shares of New OmniAb Common Stock issuable upon the exercise of the APAC Private Placement Warrants.

(8)

Represents the Base Scenario plus 1,666,667 shares of New OmniAb Common Stock issuable upon the exercise of the APAC Warrants issued in the Forward Purchase.

(9)

Represents the Base Scenario plus 1,666,667 shares of New OmniAb Common Stock (only in the maximum redemption scenario) issuable upon the exercise of the APAC Warrants issued in the Redemption Backstop.

(10)

Represents the Base Scenario plus 500,000 shares of New OmniAb Common Stock issuable pursuant to the repayment of the convertible promissory note.

(11)

Represents the Base Scenario plus the 1,402,039 shares of New OmniAb Common Stock underlying the OmniAb RSUs and OmniAb PSUs.

(12)

Represents the Base Scenario plus the shares of New OmniAb Common Stock proposed to be reserved and issuable under the 2022 Plan in each redemption scenario (representing 14% of the sum of (i) the Base Scenario, (ii) all 1,402,039 shares of New OmniAb Common Stock underlying the OmniAb RSUs and OmniAb PSUs and (iii) 866,369 OmniAb Options calculated on a “net-exercised” basis as of the Closing Date, assuming shares are surrendered having a Fair Market Value on the Closing Date equal to the exercise price of such options (rounded up to the nearest whole share, and determined without regard to the vested status of the option).

(13)

Represents the Base Scenario plus the shares of New OmniAb Common Stock proposed to be reserved and issuable under the ESPP in each redemption scenario (representing 1.5% of the sum of (i) the Base Scenario, (ii) all 1,402,039 shares of New OmniAb Common Stock underlying the OmniAb RSUs and OmniAb PSUs and (iii) 866,369 OmniAb Options calculated on a “net-exercised” basis as of the Closing Date, assuming shares are surrendered having a Fair Market Value on the Closing Date equal to the exercise price of such options (rounded up to the nearest whole share, and determined without regard to the vested status of the option).

If a public shareholder exercises its redemption rights, such exercise will not result in the loss of any warrants that it may hold. We cannot predict the ultimate value of the APAC Warrants following the consummation of the Business Combination, but assuming that 100% or 23,000,000 shares of Class A Stock held by our public shareholders were redeemed, the 7,666,667 retained outstanding APAC Public Warrants would have an aggregate value of $[•], based on a price per APAC Public Warrant of $[•] on [•], 2022, the most recent practicable date prior to the date of this proxy statement/prospectus/information statement.

For further details, see “Shareholder Proposal No. 1 — The Business Combination Proposal — The Merger Agreement — Consideration.”

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How has the announcement of the Business Combination affected the trading price of the APAC Class A Ordinary Shares?

On March 22, 2022, the last trading date before the public announcement of the execution of the Merger Agreement, the reported closing price on Nasdaq of the APAC Units, APAC Class A Ordinary Shares and APAC Public Warrants was $10.14, $10.01 and $0.30, respectively. On [•], 2022, the most recent practicable date prior to the date of this proxy statement/prospectus/information statement, the reported closing price on Nasdaq of the APAC Units, APAC Class A Ordinary Shares and APAC Public Warrants was $[•], $[•] and $[•], respectively.

Will APAC and OmniAb obtain new financing in connection with the Business Combination?

Yes. The Sponsor has agreed to purchase in the aggregate 1,500,000 shares of New OmniAb Common Stock and warrants to acquire 1,666,667 shares of New OmniAb Common Stock for $15,000,000 of gross proceeds, or $10.00 per share of New OmniAb Common Stock, in the Forward Purchase. Ligand has agreed to contribute $15,000,000 (less certain transaction and other expenses) to OmniAb prior to the Distribution pursuant to the Separation Agreement.

In addition, the Sponsor has agreed to purchase in the aggregate up to 10,000,000 shares of New OmniAb Common Stock, for up to $100,000,000, or $10.00 per share of New OmniAb Common Stock, in the Redemption Backstop as well as up to an additional 1,666,667 New OmniAb Warrants. The number of shares to be purchased in the Redemption Backstop, if any, will be in an amount sufficient to backstop redemptions by public shareholders in the event shareholder redemptions would result in less than $100,000,000 of cash proceeds being available to the combined company following the Business Combination from APAC’s trust account. The Forward Purchase is contingent upon, among other things, the Closing. See “Shareholder Proposal No. 1 — The Business Combination Proposal — Summary of the Ancillary Agreements — Amended and Restated Forward Purchase Agreement.”

Why is APAC proposing the Domestication?

The APAC Board believes that there are significant advantages to us that will arise as a result of a change of APAC’s domicile to Delaware. Further, the APAC Board believes that any direct benefit that the DGCL provides to a corporation also indirectly benefits its stockholders, who are the owners of the corporation. The APAC Board believes that there are several reasons why a reincorporation in Delaware is in the best interests of APAC and its shareholders, including, (i) the prominence, predictability and flexibility of the DGCL, (ii) Delaware’s well-established principles of corporate governance and (iii) the increased ability for Delaware corporations to attract and retain qualified directors. Each of the foregoing are discussed in greater detail in the section entitled “Shareholder Proposal No. 2 — The Domestication Proposal — Reasons for the Domestication.” To effect the Domestication, APAC will file the documents required pursuant to the Cayman Islands Companies Act with the Cayman Islands Registrar of Companies, and file a certificate of incorporation and a certificate of corporate domestication with the Secretary of State of the State of Delaware.

Will the Domestication and the Merger occur on the same day?

No. The Domestication will occur on or prior to the business day immediately prior to the Merger.

What changes will be made to the current constitutional documents of APAC?

APAC’s shareholders are being asked to consider and vote upon a proposal to approve the replacement of APAC’s Cayman Constitutional Documents under the Cayman Islands Companies Act with the Proposed Organizational Documents under the DGCL, which will be materially modified from the Cayman Constitutional Documents in the following respects:

•

change the purpose of New OmniAb to engage in “any lawful act or activity for which a corporation may be organized under the DGCL;

•

provide that the affirmative vote of the holders of at least 66 2/3% of the voting power of all then-outstanding shares of New OmniAb Common Stock entitled to vote generally in the election of directors, voting together as a single class, is required to adopt, amend or repeal the Proposed Bylaws

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and the provisions in the Proposed Certificate of Incorporation related to Directors, Indemnification and Limitation on Liability of Directors and Officers, Forum Selection and Amendments;

•

change the name of APAC to “OmniAb, Inc.,” delete the provisions relating to APAC’s status as a blank check company and retain the default of perpetual existence under the DGCL;

•

change the authorized shares of all classes of capital stock to 1,100,000,000 shares, consisting of 1,000,000,000 shares of New OmniAb Common Stock and 100,000,000 shares of preferred stock;

•

adopt Delaware as the exclusive forum for certain stockholder litigation that could be brought in the future against New OmniAb and its directors; and

•

classify the OmniAb board of directors into three (3) classes, with only one class of directors being elected in each year and each class serving a three (3)-year term.

See “Shareholder Proposal No. 3 — The Organizational Documents Proposal” for additional information.

How will the Domestication affect my APAC ordinary shares, warrants and units?

As a result of and upon the effective time of the Domestication, (1) each then issued and outstanding APAC Class A Ordinary Share will convert automatically, on a one-for-one basis, into a share of New OmniAb Common Stock, (2) each then issued and outstanding APAC Class B Ordinary Share will convert automatically, on a one-for-one basis, into a share of New OmniAb Common Stock; (3) each then issued and outstanding APAC warrant will convert automatically into a New OmniAb Warrant, pursuant to the Warrant Agreement and (4) each then issued and outstanding unit of APAC that has not been previously separated into the underlying APAC Class A Ordinary Share and underlying fractional APAC Warrant upon the request of the holder thereof, will be separated and will entitle the holder thereof to one share of New OmniAb Common Stock and one-third of one New OmniAb Warrant. See “Shareholder Proposal No. 2 — The Domestication Proposal” for additional information.

What are the material U.S. federal income tax consequences of the Domestication?

As discussed more fully under “Material U.S. Federal Income Tax Consequences to APAC Shareholders,” the Domestication will qualify as a reorganization within the meaning of Section 368(a)(1)(F) of the Code. U.S. Holders (as defined in “Material U.S. Federal Income Tax Consequences to APAC Shareholders”) of APAC Public Securities on the date of the Domestication may be subject to Section 367(b) of the Code, which applies to the domestication of a foreign corporation in a reorganization, and imposes U.S. federal income tax on certain U.S. persons in connection with transactions that would generally otherwise be tax-deferred. As a result:

•

A U.S. Holder who beneficially owns (actually or constructively) APAC Class A Ordinary Shares with a fair market value totaling $50,000 or more but who, on the date of the Domestication, owns (actually or constructively) less than 10% of the total combined voting power of all classes of APAC shares entitled to vote and less than 10% of the total value of all classes of APAC shares generally should recognize gain (but not loss) on the exchange of APAC Class A Ordinary Shares for New OmniAb Common Stock pursuant to the Domestication. As an alternative to recognizing gain, such U.S. Holder may file an election to include in income as a deemed dividend the all “earnings and profits amount” (as defined in the Treasury Regulations under Section 367 of the Code) attributable to such U.S. Holder’s APAC Class A Ordinary Shares, provided certain other requirements are satisfied; and

•

A U.S. Holder who beneficially owns (actually or constructively) APAC Class A Ordinary Shares with a fair market value totaling less than $50,000 on the date of the Domestication generally should not be required to recognize any gain or loss or include any part of APAC’s all “earnings and profits amount” in income.

APAC does not expect to have significant cumulative earnings and profits, if any, on the date of the Domestication.

If APAC were to be treated as a “passive foreign investment company” (“PFIC”) for U.S. federal income tax purposes, certain U.S. Holders may be subject to adverse tax consequences as a result of

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the Domestication. As discussed more fully below under the caption “Material U.S. Federal Income Tax Consequences to APAC Shareholders — Passive Foreign Investment Company Rules,” because APAC is a blank check company with no current active business, it is possible the IRS could assert that APAC is a PFIC.

If finalized in their proposed form, proposed Treasury Regulations may require taxable gain recognition by a U.S. Holder with respect to its exchange of APAC Class A Ordinary Shares for New OmniAb Common Stock pursuant to the Domestication if APAC were classified as a PFIC at any time during such U.S. Holder’s holding period for such APAC Class A Ordinary Shares. The tax on any such recognized gain would be imposed based on a complex set of computational rules. Such rules are discussed more fully below under “Material U.S. Federal Income Tax Consequences to APAC Shareholders.” However, a U.S. Holder may be able to avoid the PFIC gain and certain other tax consequences associated with PFIC status with respect to its APAC Class A Ordinary Shares if such U.S. Holder either (i) is eligible to and makes a timely and valid QEF Election (as defined and described below under “Material U.S. Federal Income Tax Consequences to APAC Shareholders”) in the first taxable year in which such U.S. Holder held (or was deemed to hold) APAC Class A Ordinary Shares and in which APAC was classified as a PFIC or (ii) makes a Mark-to-Market Election (as described below under “Material U.S. Federal Income Tax Consequences to APAC Shareholders”) with respect to such U.S. Holder’s APAC Class A Ordinary Shares.

Additionally, the Domestication is not expected to result in material U.S. federal income tax consequences to Non-U.S. Holders (as defined in “Material U.S. Federal Income Tax Consequences to APAC Shareholders”) of APAC Public Securities. However, Non-U.S. Holders may become subject to U.S. federal income withholding taxes on any amounts treated as dividends paid (or deemed paid) in respect of such Non-U.S. Holder’s New OmniAb Common Stock after the Domestication.

The rules governing the U.S. tax treatment of the Domestication are complex and will depend on a Holder’s particular circumstances. All Holders are urged to consult their tax advisor regarding the tax consequences to them of the Domestication, including without limitation the applicability and effect of U.S. federal, state, local and non-U.S. tax laws. For a more complete discussion of the U.S. federal income tax consequences of the Domestication, see “Material U.S. Federal Income Tax Consequences to APAC Shareholders.”

Do I have redemption rights?

If you are a holder of public shares, you have the right to request that we redeem all or a portion of your public shares for cash provided that you follow the procedures and deadlines described elsewhere in this proxy statement/prospectus/information statement. Public shareholders may elect to redeem all or a portion of the public shares held by them regardless of how they vote in respect of the Business Combination Proposal. If you wish to exercise your redemption rights, please see the answer to the question: “How do I exercise my redemption rights?”

Notwithstanding the foregoing, a public shareholder, together with any affiliate of such public shareholder or any other person with whom such public shareholder is acting in concert or as a “group” (as defined in Section 13(d)(3) of the Exchange Act), will be restricted from redeeming its public shares with respect to more than an aggregate of 15% of the public shares. Accordingly, if a public shareholder, alone or acting in concert or as a group, seeks to redeem more than 15% of the public shares, then any such shares in excess of that 15% limit would not be redeemed for cash. The Sponsor has agreed to waive its redemption rights with respect to all of the founder shares in connection with the consummation of the Business Combination. The founder shares will be excluded from the pro rata calculation used to determine the per-share redemption price.

Will how I vote affect my ability to exercise redemption rights?

No. You may exercise your redemption rights whether you vote your APAC Class A Ordinary Shares for or against or abstain from voting on the Business Combination Proposal or any other proposal to be voted upon at the extraordinary general meeting. As a result, the Business Combination can be approved by shareholders who will redeem their shares and no longer remain shareholders.

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How do I exercise my redemption rights?

If you are a public shareholder and wish to exercise your right to redeem your public shares, you must:

(i)

(a) hold public shares, or (b) if you hold public shares through units, you must elect to separate your units into the underlying public shares and public warrants prior to exercising your redemption rights with respect to the public shares;

(ii)

(iii)

deliver your public shares to Continental, APAC’s transfer agent, physically or electronically through The Depository Trust Company (“DTC”).

The address of Continental, APAC’s transfer agent, is listed under the question “Who can help answer my questions?” below.

Holders of units must elect to separate the units into the underlying public shares and public warrants prior to exercising redemption rights with respect to the public shares. If holders hold their units in an account at a brokerage firm or bank, holders must notify their broker or bank that they elect to separate the units into the underlying public shares and public warrants, or if a holder holds units registered in its own name, the holder must contact Continental, APAC’s transfer agent, directly and instruct them to do so.

Public shareholders will be entitled to request that their public shares be redeemed for a pro rata portion of the amount then on deposit in the trust account calculated as of two business days prior to the consummation of the Business Combination, including interest earned on the funds held in the trust account and not previously released to us (net of taxes payable). For illustrative purposes, as of [•], 2022, this would have amounted to approximately $[•] per issued and outstanding public share. However, the proceeds deposited in the trust account could become subject to the claims of APAC’s creditors, if any, which could have priority over the claims of the public shareholders, regardless of whether such public shareholder votes or, if they do vote, irrespective of if they vote for or against the Business Combination Proposal. Therefore, the per share distribution from the trust account in such a situation may be less than originally expected due to such claims. Whether you vote, and if you do vote, irrespective of how you vote on any proposal, including the Business Combination Proposal, will have no impact on the amount you will receive upon exercise of your redemption rights. It is expected that the funds to be distributed to public shareholders electing to redeem their public shares will be distributed promptly after the consummation of the Business Combination.

An APAC shareholder may not withdraw a redemption request once submitted to APAC unless the APAC Board determines (in its sole discretion) to permit the withdrawal of such redemption request (which the APAC Board may do in whole or in part). If you submit a redemption request to Continental, APAC’s transfer agent, and later decide prior to the extraordinary general meeting not to elect redemption, you may request to withdraw the redemption request. You may make such request by contacting Continental, APAC’s transfer agent, at the phone number or address listed in see “Questions and answers — Q: Who can help answer my questions?”

Any corrected or changed written exercise of redemption rights must be received by Continental, APAC’s transfer agent, prior to the vote taken on the Business Combination Proposal at the extraordinary general meeting. No request for redemption will be honored unless the holder’s public shares have been delivered (either physically or electronically) to Continental, APAC’s agent, at least two business days prior to the vote at the extraordinary general meeting.

If a holder of public shares properly makes a request for redemption and the public shares are delivered as described above, then, if the Business Combination is consummated, New OmniAb will redeem

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the public shares for a pro rata portion of funds deposited in the trust account, calculated as of two business days prior to the consummation of the Business Combination. The redemption will take place following the Domestication and, accordingly, it is shares of New OmniAb Common Stock that will be redeemed immediately after consummation of the Business Combination.

If you are a holder of public shares and you exercise your redemption rights, such exercise will not result in the loss of any warrants that you may hold.

If I am a holder of units, can I exercise redemption rights with respect to my units?

No. Holders of issued and outstanding units must elect to separate the units into the underlying public shares and public warrants prior to exercising redemption rights with respect to the public shares. If you hold your units in an account at a brokerage firm or bank, you must notify your broker or bank that you elect to separate the units into the underlying public shares and public warrants, or if you hold units registered in your own name, you must contact Continental, APAC’s transfer agent, directly and instruct them to do so. You are requested to cause your public shares to be separated and delivered to Continental, APAC’s transfer agent, by 5:00 p.m., Eastern Time, on [•], 2022 (two business days before the extraordinary general meeting) in order to exercise your redemption rights with respect to your public shares.

What are the material U.S. federal income tax consequences of exercising my redemption rights?

The receipt of cash by a Holder (as defined below in “Material U.S. Federal Income Tax Consequences to APAC Shareholders”) of New OmniAb Common Stock in redemption of such stock will be a taxable event for U.S. federal income tax purposes in the case of a U.S. Holder (as defined below in “Material U.S. Federal Income Tax Consequences to APAC Shareholders”) and may be a taxable event for U.S. federal income tax purposes in the case of a Non-U.S. Holder (defined below in “Material U.S. Federal Income Tax Consequences to APAC Shareholders”). Please see the discussion below under the caption “Material U.S. Federal Income Tax Consequences to APAC Shareholders — U.S. Federal Income Taxation of U.S. Holders — Redemption of New OmniAb Stock” or “Material U.S. Federal Income Tax Consequences to APAC Shareholders — U.S. Federal Income Taxation of Non-U.S. Holders — Redemption of New OmniAb Stock,” as applicable, for additional information.

Additionally, because the Domestication will occur prior to the redemption of any Holder, U.S. Holders exercising redemption rights will be subject to the potential tax consequences of Section 367 of the Code as well as potential tax consequences of the U.S. federal income tax rules relating to PFICs. The tax consequences of Section 367 of the Code and the PFIC rules are discussed more fully below under “Material U.S. Federal Income Tax Consequences to APAC Shareholders.”

All Holders should consult with their own tax advisors with respect to the U.S. federal income tax consequences of exercising such redemption rights.

What happens to the funds deposited in the trust account after consummation of the Business Combination?

Following the closing of APAC’s initial public offering, an amount equal to $235,750,000 of the net proceeds from APAC’s initial public offering and the sale of the APAC Private Placement Warrants was placed in the trust account. As of April 21, 2022, funds in the trust account totaled approximately $235,818,000 and were comprised entirely of cash, U.S. government treasury obligations with a maturity of 185 days or less or of money market funds meeting certain conditions under Rule 2a-7 under the Investment Company Act of 1940, as amended (the “Investment Company Act”), which invest only in direct U.S. government treasury obligations. These funds will remain in the trust account, except for the withdrawal of interest to pay taxes, if any, until the earliest of (1) the completion of a business combination (including the Business Combination), (2) the redemption of any public shares properly tendered in connection with a shareholder vote to amend the Cayman Constitutional Documents to modify the substance or timing of APAC’s obligation to redeem 100% of the public shares if it does not complete a business combination by February 12, 2023 and (3) the redemption of all of the public shares if APAC is unable to complete a business combination by February 12, 2023 (or if such date is further extended at a duly called extraordinary general meeting, such later date), subject to applicable law.

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Upon consummation of the Business Combination, the funds deposited in the trust account will be released to pay holders of New OmniAb public shares who properly exercise their redemption rights, to pay transaction fees and expenses associated with the Business Combination and for working capital and general corporate purposes of OmniAb following the Business Combination. See “Summary of the Proxy Statement/Prospectus/Information Statement — Sources and Uses of Funds for the Business Combination.”

What happens if a substantial number of the public shareholders vote in favor of the Business Combination Proposal and exercise their redemption rights?

Our public shareholders may vote in favor of the Business Combination and exercise their redemption rights. Accordingly, the Business Combination may be consummated even though the funds available from the trust account and the number of public shareholders are reduced as a result of redemptions by public shareholders.

The Merger Agreement provides that the obligations of the parties to consummate the Merger are conditioned on, among other things, that as of the Closing and, to the extent necessary, the Redemption Backstop shall have been consummated. If such condition is not met, and such condition is not waived under the terms of the Merger Agreement, then the Merger Agreement could terminate and the proposed Business Combination may not be consummated. In addition, with fewer public shares and public shareholders, the trading market for our New OmniAb Common Stock may be less liquid than the market for our APAC Class A Ordinary Shares was prior to the Closing and we may not be able to continue to meet the listing standards for Nasdaq. With less funds available from the trust account, the working capital infusion from the trust account into New OmniAb’s business will be reduced. Further, in no event will we redeem public shares in an amount that would cause New OmniAb’s net tangible assets (as determined in accordance with Rule 3a5 1-1 (g)(1) of the Exchange Act) to be less than $5,000,001.

When do you expect the Business Combination to be completed?

The Business Combination is expected to be completed in the fourth quarter of 2022.

Do I have appraisal rights in connection with the proposed Business Combination and the proposed Domestication?

Neither APAC’s shareholders nor APAC’s warrant holders have appraisal rights in connection with the Business Combination or the Domestication under the Cayman Islands Companies Act or under the DGCL.

Do I have dissenters’ rights or appraisal rights in connection with the proposed Business Combination and the proposed Merger?

As APAC is not a constituent party to the Merger between Merger Sub and OmniAB, shareholders of APAC do not have dissenters’ rights in connection with the Merger under Cayman Islands law.

APAC’s warrant holders do not have appraisal rights in connection with the Business Combination or the Merger under the Cayman Islands Companies Act or under the DGCL.

What do I need to do now?

APAC urges you to read this proxy statement/prospectus/information statement, including the Annexes and the documents referred to herein, carefully and in their entirety and to consider how the Business Combination will affect you as a shareholder or warrant holder of APAC. APAC’s shareholders should then vote as soon as possible in accordance with the instructions provided in this proxy statement/prospectus/information statement and on the enclosed proxy card.

How do I vote?

The extraordinary general meeting will be held at 10:00 a.m., Eastern Time, on [•], 2022, at the offices of Weil, Gotshal & Manges LLP, located at 767 Fifth Avenue, New York, NY 10153 and via live webcast at https://www.cstproxy.com/avistapac/2022, where you will be able to listen to the meeting live and

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vote during the meeting. If you are a holder of record of ordinary shares on the APAC Record Date for the extraordinary general meeting, you may vote at the extraordinary general meeting in person, via the virtual meeting platform or by submitting a proxy for the extraordinary general meeting, in any of the following ways, if available:

Vote by Mail: by signing, dating and returning the enclosed proxy card in the accompanying prepaid reply envelope. By signing the proxy card and returning it in the enclosed prepaid envelope to the specified address, you are authorizing the individuals named on the proxy card to vote your shares at the extraordinary general meeting in the manner you indicate. We encourage you to sign and return the proxy card even if you plan to attend the extraordinary general meeting so that your shares will be voted if you are unable to attend the extraordinary general meeting. If you receive more than one proxy card, it is an indication that your shares are held in multiple accounts. Please sign and return all proxy cards to ensure that all of your shares are voted. If you hold your shares in “street name” through a bank, broker or other nominee, you will need to follow the instructions provided to you by your bank, broker or other nominee to ensure that your shares are represented and voted at the extraordinary general meeting. If you sign and return the proxy card but do not give instructions on how to vote your shares, your ordinary shares will be voted as recommended by the APAC Board.

Vote by Internet: visit cstproxyvote.com, 24 hours a day, seven days a week, until 11:59 p.m., Eastern Time on [•], 2022 (have your proxy card in hand when you visit the website);

Vote by Phone: by calling toll-free (within the U.S. or Canada) 1 800-450-7155 or by calling +1 857-999-9155 if you are outside of the U.S. and Canada (have your proxy card in hand when you call); or

Vote at the extraordinary general meeting: you can attend the extraordinary general meeting in person or via the virtual meeting platform and vote during the meeting by following the instructions on your proxy card. You can access the extraordinary general meeting by visiting the website https://www.cstproxy.com/avistapac/2022. You will need your control number for access. Instructions on how to virtually attend and participate at the extraordinary general meeting are available at https://www.cstproxy.com/avistapac/2022/proxy.

If you hold your shares in “street name,” which means your shares are held of record by a broker, bank or nominee, you should contact your broker, bank or nominee to ensure that votes related to the shares you beneficially own are properly counted. In this regard, you must provide the broker, bank or nominee with instructions on how to vote your shares or, if you wish to attend the extraordinary general meeting and vote in person, obtain a valid proxy from your broker, bank or nominee. In most cases you may vote by telephone or over the Internet as instructed.

If my shares are held in “street name,” will my broker, bank or nominee automatically vote my shares for me?

No. If your shares are held in a stock brokerage account or by a bank or other nominee, you are considered the “beneficial holder” of the shares held for you in what is known as “street name.” If this is the case, this proxy statement/prospectus/information statement may have been forwarded to you by your brokerage firm, bank or other nominee, or its agent, and you may need to obtain a proxy form from the institution that holds your shares and follow the instructions included on that form regarding how to instruct your broker, bank or nominee as to how to vote your shares. Under the rules of various national and regional securities exchanges, your broker, bank, or nominee cannot vote your shares with respect to non-discretionary matters unless you provide instructions on how to vote in accordance with the information and procedures provided to you by your broker, bank, or nominee. We believe all the proposals presented to the shareholders will be considered non-discretionary and therefore your broker, bank, or nominee cannot vote your shares without your instruction. Your bank, broker, or other nominee can vote your shares only if you provide instructions on how to vote. As the beneficial holder, you have the right to direct your broker, bank or other nominee as to how to vote your shares and you should instruct your broker to vote your shares in accordance with directions you provide. If you do not provide voting instructions to your broker on a particular proposal on which your broker does not have discretionary authority to vote, your shares will not be voted on that

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proposal. This is called a “broker non-vote.” A broker non-vote, while considered present for the purposes of establishing a quorum, will not count as a vote cast at the extraordinary general meeting.

When and where will the extraordinary general meeting be held?

The extraordinary general meeting will be held on [•], 2022 at 10:00 a.m., Eastern Time, at the offices of Weil, Gotshal & Manges LLP, located at 767 Fifth Avenue, New York, NY 10153. Cayman Islands law requires there be a physical location for the meeting. However, given the ongoing global pandemic, APAC encourages its shareholders to attend, via live webcast at https://www.cstproxy.com/avistapac/2022. To participate in the virtual meeting, an APAC shareholder of record will need the 12-digit control number included on their proxy card or instructions that accompanied their proxy materials, if applicable, or to obtain a proxy form from their broker, bank or other nominee. The extraordinary general meeting webcast will begin promptly at 10:00 a.m., Eastern Time. APAC shareholders are encouraged to access the APAC extraordinary general meeting prior to the start time. If you encounter any difficulties accessing the virtual meeting or during the meeting time, please call the technical support number that will be posted on the virtual meeting login page.

Who is entitled to vote at the extraordinary general meeting?

APAC has fixed September 1, 2022 as the APAC Record Date for the extraordinary general meeting. If you were a shareholder of APAC at the close of business on the APAC Record Date, you are entitled to vote on matters that come before the extraordinary general meeting. However, a shareholder may only vote his or her shares if he or she is present in person or is represented by proxy at the extraordinary general meeting.

How many votes do I have?

APAC shareholders are entitled to one vote at the extraordinary general meeting for each ordinary share held of record as of the APAC Record Date. As of the close of business on the APAC Record Date for the extraordinary general meeting, there were 23,000,000 APAC Class A Ordinary Shares issued and outstanding, and 5,750,000 APAC Class B Ordinary Shares issued and outstanding.

What constitutes a quorum?

A quorum of APAC shareholders is necessary to hold a valid meeting. A quorum will be present at the extraordinary general meeting if one or more shareholders who together hold not less than one-third of the issued and outstanding ordinary shares entitled to vote at the extraordinary general meeting are in attendance in person or by proxy. As of the APAC Record Date for the extraordinary general meeting, 9,583,334 ordinary shares would be required to achieve a quorum.

What vote is required to approve each proposal at the extraordinary general meeting?

The following votes are required for each proposal at the extraordinary general meeting:

(i)

Business Combination Proposal: The approval of the Business Combination Proposal requires a special resolution under Cayman Islands law, being the affirmative vote of the holders of a majority of at least two-thirds of the ordinary shares represented in person, virtually or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting.

(ii)

Domestication Proposal: The approval of the Domestication Proposal requires a special resolution under Cayman Islands law, being the affirmative vote of the holders of a majority of at least two-thirds of the ordinary shares represented in person, virtually or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting. With respect to the Domestication Proposal, a holder of APAC Class B Ordinary Shares shall have ten votes for every APAC Class B Ordinary Share of which he or she is the holder and a holder of APAC Class A Ordinary Shares shall have one vote for every APAC Class A Ordinary Share of which he or she is the holder.

(iii)

Organizational Documents Proposal: The approval of the Organizational Documents Proposal requires a special resolution under Cayman Islands law, being the affirmative vote of the holders of

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a majority of at least two-thirds of the ordinary shares represented in person, virtually or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting.

(iv)

Non-Binding Governance Proposals: The Non-Binding Governance Proposals are constituted of non-binding advisory proposals, and may be approved by ordinary resolution, being the affirmative vote of the holders of a majority of the ordinary shares represented in person, virtually or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting.

(v)

Director Election Proposal: The approval of the Director Election Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of the holders of a majority of the ordinary shares represented in person, virtually or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting. With respect to the Director Election Proposal, only the holders of the APAC Class B Ordinary Shares are entitled to vote.

(vi)

Stock Issuance Proposal: The approval of the Stock Issuance Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of the holders of a majority of the ordinary shares represented in person, virtually or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting.

(vii)

Incentive Plan Proposal: The approval of the Incentive Plan Proposal may be approved by an ordinary resolution under Cayman Islands law, being the affirmative vote of the holders of a majority of the ordinary shares represented in person, virtually or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting.

(viii)

ESPP Proposal: The approval of the ESPP Proposal may be approved by an ordinary resolution under Cayman Islands law, being the affirmative vote of the holders of a majority of the ordinary shares represented in person, virtually or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting.

(ix)

Adjournment Proposal: The approval of the Adjournment Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of the holders of a majority of the ordinary shares represented in person, virtually or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting.

What are the recommendations of the APAC Board?

The APAC Board believes that the Business Combination Proposal and the other proposals to be presented at the extraordinary general meeting are in the best interest of APAC’s shareholders and unanimously recommends that its shareholders vote “FOR” the Business Combination Proposal, “FOR” the Domestication Proposal, “FOR” the Organizational Documents Proposal, and “FOR” all of the other proposals. The existence of financial and personal interests of one or more of APAC’s directors may result in a conflict of interest on the part of such director(s) between what he, she or they may believe is in the best interests of APAC and its shareholders and what he, she or they may believe is best for himself, herself or themselves in determining to recommend that shareholders vote for the proposals. In addition, APAC’s officers have interests in the Business Combination that may conflict with your interests as a shareholder. See the section entitled “Shareholder Proposal No. 1 — The Business Combination Proposal — Interests of APAC’s Directors and Executive Officers in the Business Combination” for a further discussion of these considerations.

How does the Sponsor intend to vote its shares?

Unlike some other blank check companies in which the initial shareholders agree to vote their shares in accordance with the majority of the votes cast by the public shareholders in connection with an initial business combination, the Sponsor has agreed to vote all the founder shares and any public shares purchased during or after APAC’s initial public offering in favor of the Business Combination. As of the date of this proxy statement/prospectus/information statement, the Sponsor (including APAC’s directors) owns 20% of the issued and outstanding ordinary shares.

The Sponsor and APAC’s directors, officers, advisors or their respective affiliates may purchase shares or warrants in privately negotiated transactions or in the open market either prior to or following the

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completion of the Business Combination. If the Sponsor or its affiliates engage in such transactions prior to the completion of the Business Combination, the purchase will be at a price no higher than the price offered through the redemption process. Any such securities purchased by the Sponsor or its affiliates, or any other third party that would vote at the direction of the Sponsor or its affiliates, will not be voted in favor of approving the Business Combination. However, they have no current commitments, plans or intentions to engage in any such transactions and have not formulated any terms or conditions for any such transactions. None of the funds in the trust account will be used to purchase shares or warrants in such transactions. If they engage in such transactions, they will not make any such purchases when they are in possession of any material non-public information not disclosed to the seller or if such purchases are prohibited by Regulation M under the Exchange Act. Such a purchase may include a contractual acknowledgement that such shareholder, although still the record holder of APAC’s shares, is no longer the beneficial owner thereof and therefore agrees not to exercise its redemption rights.

In the event that the Sponsor or APAC’s directors, officers, advisors or their affiliates purchase shares in privately negotiated transactions from public shareholders who have already elected to exercise their redemption rights, such selling shareholders would be required to revoke their prior elections to redeem their shares. The Sponsor and its affiliates have entered into an agreement with APAC, pursuant to which they have agreed to waive their redemption rights with respect to their founder shares and public shares.

The purpose of such purchases would be to (i) ensure that such shares would not be redeemed in connection with the initial business combination or (ii) ensure that APAC’s net tangible assets are at least $5,000,001, where it appears that such requirement would otherwise not be met. Any such purchases of our securities may result in the completion of the Business Combination that may not otherwise have been possible.

In addition, if such purchases are made, the public “float” of APAC Class A Ordinary Shares may be reduced and the number of beneficial holders of our securities may be reduced, which may make it difficult to maintain or obtain the quotation, listing or trading of our securities on a national securities exchange.

The Sponsor and APAC’s officers, directors and/or their affiliates anticipate that they may identify the shareholders with whom the Sponsor or APAC’s officers, directors or their affiliates may pursue privately negotiated purchases by either the shareholders contacting us directly or by our receipt of redemption requests submitted by shareholders (in the case of Class A Ordinary Shares) following our mailing of proxy materials in connection with the Business Combination. To the extent that the Sponsor or APAC’s officers, directors, advisors or their affiliates enter into a private purchase, they would identify and contact only potential selling shareholders who have expressed their election to redeem their shares for a pro rata share of the trust account or vote against the Business Combination Proposal but only if such shares have not already been voted at the extraordinary general meeting. The Sponsor and APAC’s officers, directors, advisors or their affiliates will only purchase shares if such purchases comply with Regulation M under the Exchange Act and the other federal securities laws.

To the extent that the Sponsor or APAC’s officers, directors, advisors or their affiliates enter into any such private purchase, prior to the Extraordinary General Meeting APAC will file a current report on Form 8-K to disclose (1) the amount of securities purchased in any such purchases, along with the purchase price; (2) the purpose of any such purchases; (3) the impact, if any, of any such purchases on the likelihood that the business combination transaction will be approved; (4) the identities or the nature of the security holders (e.g., 5% security holders) who sold their securities in any such purchases; and (5) the number of securities for which APAC has received redemption requests pursuant to its shareholders' redemption rights in connection with the Business Combination.

Any purchases by the Sponsor or APAC’s officers, directors and/or their affiliates who are affiliated purchasers under Rule 10b-18 under the Exchange Act will only be made to the extent such purchases are able to be made in compliance with Rule 10b-18, which is a safe harbor from liability for manipulation under Section 9(a)(2) and Rule 10b-5 of the Exchange Act. Rule 10b-18 has certain technical requirements that must be complied with in order for the safe harbor to be available to the purchaser.

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The Sponsor and APAC’s officers, directors and/or their affiliates will not make purchases of APAC Class A Ordinary Shares if the purchases would violate Section 9(a)(2) or Rule 10b-5 of the Exchange Act.

What happens if I sell my APAC ordinary shares before the extraordinary general meeting?

The APAC Record Date for the extraordinary general meeting is earlier than the date of the extraordinary general meeting and earlier than the date that the Business Combination is expected to be completed. If you transfer your public shares after the applicable APAC Record Date, but before the extraordinary general meeting, unless you grant a proxy to the transferee, you will retain your right to vote at such general meeting but the transferee, and not you, will have the ability to redeem such shares (if time permits).

May I change my vote after I have delivered my signed proxy card or voting instruction card?

Yes. If you are a shareholder of record of APAC ordinary shares as of the close of business on the APAC Record Date, you can change or revoke your proxy before it is voted at the meeting in one of the following ways:

•

Submit a new proxy card bearing a later date; or

•

Vote in person or electronically at the extraordinary general meeting by visiting https://www.cstproxy.com/avistapac/2022 and entering the control number found on your proxy card, voting instruction form or notice you previously received. Please note that your attendance at the extraordinary general meeting will not alone serve to revoke your proxy.

What happens if I fail to take any action with respect to the extraordinary general meeting?

If you fail to take any action with respect to the extraordinary general meeting and the Business Combination is approved by shareholders and the Business Combination is consummated, you will become a stockholder or warrant holder of New OmniAb. If you fail to take any action with respect to the extraordinary general meeting and the Business Combination Proposal and the other Condition Precedent Proposals are not approved, you will remain a shareholder or warrant holder of APAC. However, if you fail to vote with respect to the extraordinary general meeting, you will nonetheless be eligible to elect to redeem your public shares in connection with the Business Combination.

What happens if I attend the extraordinary general meeting and abstain or do not vote?

For purposes of the APAC extraordinary general meeting, an abstention occurs when a shareholder is present at the APAC extraordinary general meeting and does not vote or returns a proxy with an “abstain” vote.

If you are a APAC shareholder that attends the APAC extraordinary general meeting in person or virtually and fails to vote on the Business Combination Proposal, the Domestication Proposal, the Organizational Documents Proposal, the Non-Binding Governance Proposals, the Director Election Proposal, the Stock Issuance Proposal, the Incentive Plan Proposal, the ESPP Proposal or the Adjournment Proposal, or if you respond to such proposals with an “abstain” vote, your failure to vote or your “abstain” vote, in each case, will have no effect on the vote count for such proposals.

What should I do with my APAC share certificates, warrant certificates or unit certificates?

APAC shareholders who exercise their redemption rights must deliver (either physically or electronically) their share certificates to Continental, APAC’s transfer agent, prior to the extraordinary general meeting.

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APAC warrant holders should not submit the certificates relating to their warrants. Public shareholders who do not elect to have their public shares redeemed for the pro rata share of the trust account should not submit the certificates relating to their public shares.

Upon the Domestication, holders of APAC Units, APAC Class A Ordinary Shares, APAC Class B Ordinary Shares and APAC Warrants will receive shares of New OmniAb Common Stock and New OmniAb Warrants, as the case may be, without needing to take any action and, accordingly, such holders should not submit any certificates relating to their units, APAC Class A Ordinary Shares (unless such holder elects to redeem the public shares in accordance with the procedures set forth above), APAC Class B Ordinary Shares or APAC Warrants.

What should I do if I receive more than one set of voting materials?

APAC shareholders may receive more than one set of voting materials, including multiple copies of this proxy statement/prospectus/information statement and multiple proxy cards or voting instruction cards. For example, if you hold your shares 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 holder of record and your shares are registered in more than one name, you will receive more than one proxy card. Please complete, sign, date and return each proxy card and voting instruction card that you receive in order to cast a vote with respect to all of your APAC ordinary shares.

Who will solicit and pay the cost of soliciting proxies for the extraordinary general meeting?

APAC will pay the cost of soliciting proxies for the extraordinary general meeting. APAC has engaged D.F. King & Co., Inc. (“D.F. King”) to assist in the solicitation of proxies for the extraordinary general meeting. APAC has agreed to pay D.F. King a fee of $25,000, plus disbursements (to be paid with non-trust account funds). APAC will also reimburse banks, brokers and other custodians, nominees and fiduciaries representing beneficial owners of APAC Class A Ordinary Shares for their expenses in forwarding soliciting materials to beneficial owners of APAC Class A Ordinary Shares and in obtaining voting instructions from those owners. APAC’s directors and officers may also solicit proxies by telephone, by facsimile, by mail, on the Internet or in person. They will not be paid any additional amounts for soliciting proxies.

Where can I find the voting results of the extraordinary general meeting?

The preliminary voting results will be expected to be announced at the extraordinary general meeting. APAC will publish final voting results of the extraordinary general meeting in a Current Report on Form 8-K within four business days after the extraordinary general meeting.

Who can help answer my questions?

If you have questions about the Business Combination or if you need additional copies of this proxy statement/prospectus/information statement, any document incorporated by reference in this proxy statement/prospectus/information statement or the enclosed proxy card, you should contact:

D.F. King & Co, Inc.
48 Wall Street, 22nd Floor
New York, NY 10005
Call Toll-Free: (888) 887-0082
Banks and Brokers Call: (212) 269-5550
AHPA@dfking.com

You also may obtain additional information about APAC from documents filed with the SEC by following the instructions in the section entitled “Where You Can Find More Information.” If you are a holder of public shares and you intend to seek redemption of your public shares, you will need to deliver your public shares (either physically or electronically) to Continental, APAC’s transfer agent, at the address below prior to the extraordinary general meeting. Holders must complete the procedures for electing to redeem their public shares in the manner described above prior to 5:00 p.m., Eastern Time, on [•], 2022 (two business

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SUMMARY OF THE PROXY STATEMENT/PROSPECTUS/INFORMATION STATEMENT

This summary highlights selected information from this proxy statement/prospectus/information statement and does not contain all of the information that is important to you. To better understand the proposals to be submitted for a vote at the extraordinary general meeting, including the Business Combination, you should read this proxy statement/prospectus/information statement, including the Annexes and other documents referred to herein, carefully and in their entirety. The Merger Agreement is the primary legal document that governs the Business Combination and the other transactions that will be undertaken in connection with the Business Combination. The Merger Agreement is also described in detail in this proxy statement/prospectus/information statement in the section entitled “Shareholder Proposal No. 1 — The Business Combination Proposal — Summary of the Merger Agreement.”

Unless otherwise specified, all share calculations (1) assume no exercise of redemption rights by the public shareholders in connection with the Business Combination and (2) do not include any shares issuable upon the exercise of the New OmniAb Warrants or underlying New OmniAb Equity Awards.

The Parties to the Business Combination

APAC

On August 12, 2021, APAC consummated its initial public offering of 23,000,000 units, including the issuance of 3,000,000 units as a result of the underwriter’s exercise in full of their over-allotment option (the “IPO”), with each unit consisting of one Class A ordinary share of APAC, par value $0.0001 per share, and one-third of one redeemable warrant of APAC, each whole warrant entitling the holder thereof to purchase one APAC Class A Ordinary Share at an exercise price of $11.50 per share, subject to adjustment (the “APAC Units”). The APAC Units were sold at a price of $10.00 per APAC Unit, generating gross proceeds of $230,000,000. Substantially concurrently with the closing of the IPO, APAC completed the private sale of the APAC Private Placement Warrants to the Sponsor, generating gross proceeds to APAC of $12,350,000. The APAC Private Placement Warrants are identical to the warrants sold as part of the APAC Units in the IPO, except that, so long as they are held by the Sponsor or its permitted transferees: (i) they (including the APAC Class A Ordinary Shares issuable upon exercise of these warrants) may not, subject to certain limited exceptions, be transferred, assigned or sold by the Sponsor until 30 days after the completion of APAC’s initial business combination and (ii) they (including the APAC Class A Ordinary Shares issuable upon exercise of these warrants) are entitled to registration rights.

A total of $235,750,000, comprised of the proceeds from the IPO and a portion of the sale of the Private Placement Warrants, were placed in a U.S.-based trust account at JP Morgan Chase Bank, N.A., maintained by Continental, acting as trustee. Except with respect to interest earned on the funds held in the trust account that may be released to APAC to pay its taxes if such funds are held in an interest-bearing account, the proceeds from the IPO will not be released from the trust account until the earliest to occur of: (i) the completion of APAC’s initial business combination; (ii) the redemption of any public shares properly tendered in connection with a shareholder vote to amend APAC’s amended and restated memorandum and articles of association (a) to modify the substance or timing of APAC’s obligation to provide holders of the APAC Class A Ordinary Shares the right to have their shares redeemed in connection with APAC’s initial business combination or to redeem 100% of its public shares if APAC does not complete its initial business combination within 18 months from the closing of the IPO or (b) with respect to any other provision relating to the rights of holders of the APAC Class A Ordinary Shares; or (iii) the redemption of all of APAC’s public shares if it has not completed its initial business combination within 18 months from the closing of the IPO.

The APAC Units, APAC Class A Ordinary Shares and APAC warrants are currently listed on the Nasdaq under the symbols “AHPAU,” “AHPA” and “AHPAW,” respectively.

APAC’s principal executive office is located at 65 East 55th Street, 18th Floor, New York, NY 10022. Its telephone number is (212) 593-6900.

Merger Sub

APAC Merger Sub Inc. (“Merger Sub”) is a Delaware corporation and a wholly-owned subsidiary of APAC. The Merger Sub does not own any material assets or operate any business and was formed for the purpose of participating in the Merger transaction.

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Ligand

Ligand is a biopharmaceutical company focused on developing or acquiring technologies that help pharmaceutical companies discover and develop medicines. Ligand Common Stock is listed on The Nasdaq Global Market under the symbol “LGND.” Ligand was incorporated under the laws of the State of Delaware on May 18, 1995. Ligand’s principal executive offices are located at 3911 Sorrento Valley Boulevard, Suite 110, San Diego, CA 92121, and its telephone number is (858) 550-7500.

OmniAb

OmniAb was incorporated under the laws of the State of Delaware on December 14, 2015 under the name Schrader 2 Acquisition, Inc. It is a wholly-owned subsidiary of Ligand. On January 8, 2016, Ligand acquired Open Monoclonal Technology, Inc., another Delaware corporation, pursuant to a multi-step transaction that resulted in the merger of that other company into Schrader 2 Acquisition, Inc. On January 8, 2016, Schrader 2 Acquisition, Inc. changed its name to Open Monoclonal Technology, Inc., and on November 10, 2021 Open Monoclonal Technology, Inc. changed its name to OmniAb, Inc. OmniAb’s principal executive offices are located at 5980 Horton Street, Suite 600, Emeryville, CA 94608, and its telephone number is (510) 250-7800. The OmniAb Business involves a suite of technologies, including a core competence focused on ion channels and transporters and a patent-protected transgenic animal platform used in the discovery of fully human monoclonal and bispecific therapeutic antibodies.

Transaction Steps

The Business Combination will be accomplished by way of the following transaction steps:

•

The Domestication will be effected, whereby APAC’s jurisdiction of incorporation will be changed by its deregistering as an exempted company in the Cayman Islands and continuing and domesticating as a corporation incorporated under the laws of the State of Delaware at least one (1) business day prior to the consummation of the Merger;

•

The Separation will be effected, whereby Ligand will, among other things and subject to the terms and conditions of the Separation Agreement, transfer the OmniAb Business, including certain related subsidiaries of Ligand, to OmniAb and make a contribution to the capital of OmniAb of $15,000,000 less certain transaction and other expenses;

•

The Distribution will be effected, whereby Ligand will distribute to Ligand stockholders 100% of the OmniAb Common Stock;

•

Pursuant to the Employee Matters Agreement, at the time of the Distribution (i) each existing Ligand equity award granted prior to March 2, 2022, with certain limited exceptions, will be split into (A) a new Ligand equity award and (B) a new OmniAb Equity Award, with any in-the-money value in the original Ligand equity award split between such awards based on the relative values of Ligand and OmniAb at the time of the Distribution, and (ii) each existing Ligand equity award granted on or after March 2, 2022 will be converted into either (A) if the holder will be a Ligand service provider following the Distribution, an adjusted Ligand equity award, or (B) if the holder will be an OmniAb service provider following the Distribution, a new OmniAb Equity Award, with the intrinsic value of such adjusted or converted award equal to the intrinsic value in the original Ligand equity award based on the relative values of Ligand and OmniAb at the time of the Distribution;

•

Pursuant to the A&R FPA, OmniAb, New OmniAb and the Sponsor will effect the Forward Purchase, whereby New OmniAb will issue and sell to the Sponsor 1,500,000 shares of New OmniAb Common Stock and warrants to acquire 1,666,667 shares of New OmniAb Common Stock for an aggregate purchase price of $15,000,000, with such purchases to be consummated following the Domestication and prior to the Merger. In addition to the Forward Purchase, the Sponsor has agreed to effect the Redemption Backstop (to the extent necessary), whereby the Sponsor will purchase up to an additional 10,000,000 shares of New OmniAb Common Stock and up to an additional 1,666,667 New OmniAb Warrants, for an aggregate additional purchase price of up to $100,000,000, in order to backstop shareholder redemptions to the extent such redemptions would result in the cash proceeds to be available to the combined company following the Business Combination from APAC’s trust account to be less than $100,000,000; and

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•

Following the above steps, the Merger will be effected, whereby Merger Sub will merge with and into OmniAb, with OmniAb continuing as the surviving company in the Merger and a wholly owned subsidiary of New OmniAb.

Proposals to be Put to the Shareholders of APAC at the Extraordinary General Meeting

The following is a summary of the proposals to be put to the extraordinary general meeting of APAC and certain transactions contemplated by the Merger Agreement. Each of the Condition Precedent Proposals is cross-conditioned on the approval of the others. The Adjournment Proposal is not conditioned upon the approval of any other proposal set forth in this proxy statement/prospectus/information statement. The Non-Binding Governance Proposals are constituted of non-binding advisory proposals. The transactions contemplated by the Merger Agreement will be consummated only if the Condition Precedent Proposals are approved at the extraordinary general meeting.

The Business Combination Proposal

At the extraordinary general meeting, APAC shareholders will be asked to consider and vote upon the Business Combination Proposal. Pursuant to the Business Combination Proposal, APAC shareholders will vote upon adoption of the Merger Agreement, the Transaction Documents and the transactions contemplated thereby. The Merger Agreement provides for, among other things, following the Domestication, the Separation, the Distribution, the Forward Purchase and the Redemption Backstop, if necessary, the merger of Merger Sub with and into OmniAb (the “Merger”), with OmniAb surviving the merger as a wholly-owned subsidiary of APAC, in accordance with the terms and subject to the conditions of the Merger Agreement as more fully described elsewhere in this proxy statement/prospectus/information statement.

After consideration of the factors identified and discussed in the section entitled “Shareholder Proposal No. 1 — The Business Combination Proposal — The APAC Boards’ Reasons for the Business Combination,” the APAC Board concluded that the Business Combination met all of the requirements disclosed in the prospectus for APAC’s initial public offering, including that the business of OmniAb and its subsidiaries had a fair market value equal to at least 80% of the net assets held in trust (net of amounts disbursed to management for working capital purposes and excluding the amount of any deferred underwriting discount held in trust).

Merger Consideration

As a result of and upon the Closing, among other things, each outstanding share of OmniAb Common Stock (other than Treasury Shares), will be cancelled upon the Effective Time in exchange for the right to receive (i) a number of shares of New OmniAb Common Stock equal to the Base Exchange Ratio, and (ii) a number of OmniAb Earnout Shares equal to the Earnout Exchange Ratio. For further details, see “Shareholder Proposal No. 1 — The Business Combination Proposal — Merger Consideration.”

In addition, all (i) OmniAb Options, (ii) OmniAb RSUs and (iii) OmniAb PSUs, in each case, that are outstanding as of immediately prior to the Effective Time, will be converted into such number of (a) New OmniAb Options, (b) New OmniAb RSUs and (c) New OmniAb PSUs, respectively, in each case, equal to (1) the number of shares of OmniAb Common Stock underlying such OmniAb Equity Awards immediately

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prior to the Effective Time multiplied by (2) the Base Exchange Ratio. Each holder of an OmniAb Option, OmniAb RSU and/or OmniAb PSU will also receive a number of OmniAb Earnout Shares equal to the number of shares of OmniAb Common Stock underlying such OmniAb Options, OmniAb RSUs and/or OmniAb PSUs, as applicable, multiplied by the Earnout Exchange Ratio, and the exercise price of each outstanding New OmniAb Option will be equal to the exercise price of the pre-conversion OmniAb Option divided by the Base Exchange Ratio. For further details, see “Shareholder Proposal No. 1 — The Business Combination Proposal — Consideration, Treatment of OmniAb Options, OmniAb RSUs and OmniAb PSUs.”

Closing Conditions

The Merger Agreement provides that the obligations of the parties to consummate the Merger are conditioned on, among other things, (i) the expiration or termination of the waiting period under the HSR Act, (ii) receipt of required consents and approvals from certain governmental authorities, (iii) no agreement between Ligand or APAC and any governmental authority pursuant to which Ligand or APAC has agreed not to consummate the Business Combination shall be in effect, (iv) no governmental authority of competent jurisdiction shall have enacted, issued or granted any law (whether temporary, preliminary or permanent), in each case that is in effect and which has the effect of restraining, enjoining or prohibiting the consummation of the transaction, (v) APAC shall have at least $5,000,001 of net tangible assets as of the Closing, (vi) the New OmniAb Common Stock issuable pursuant to the Business Combination shall have been approved for listing on Nasdaq, subject to official notice of issuance, (vii) Ligand, OmniAb, APAC and Merger Sub shall each have performed and complied in all material respects with the obligations, covenants and agreements required by the Merger Agreement to be performed or complied with by it at or prior to the Effective Time (viii) customary bring down conditions related to the accuracy of the parties’ respective representations and warranties in the Merger Agreement, (ix) the consummation of the Separation, the Distribution and the other transactions contemplated by the Separation Agreement, (x) each of APAC’s and OmniAb’s registration statements to be filed with the United States Securities and Exchange Commission shall have become effective, (xi) APAC’s shareholder approval of the Condition Precedent Proposals shall have been obtained and (xii) the receipt by Ligand and APAC of certain tax opinions.

In addition, the respective obligations of OmniAb and Ligand to consummate the Business Combination is conditioned upon, among other items, the completion of the Forward Purchase and the Redemption Backstop, the resignation of all directors and all executive officers of APAC and the occurrence of the Domestication. APAC’s obligation to consummate the Business Combination is also conditioned on there having been no “Material Adverse Effect” on OmniAb since the date of the Merger Agreement.

To the extent permitted under applicable law, the foregoing conditions, including the conditions in the Merger Agreement related to the receipt by Ligand and APAC of certain tax opinions, may be waived by the applicable party or parties in writing. To the extent that the APAC Board or the Ligand Board determines that any modifications by the parties, including any waivers of any conditions to the Closing, materially change the terms of the Business Combination, APAC and Ligand will notify their respective stockholders in a manner reasonably calculated to inform them about the modifications as may be required by law, by publishing a press release, filing a current report on Form 8-K and/or circulating a supplement to this proxy statement/prospectus/information statement. For further details, see “Shareholder Proposal No. 1 — The Business Combination Proposal — Summary of the Merger Agreement.”

Domestication Proposal

APAC will ask its shareholders to approve by special resolution the Domestication Proposal. As a condition to closing the Business Combination pursuant to the terms of the Merger Agreement, the APAC Board has unanimously approved the Domestication Proposal. If approved, APAC’s jurisdiction of incorporation will be changed by its deregistering as an exempted company in the Cayman Islands and continuing and domesticating as a corporation incorporated under the laws of the State of Delaware at least one (1) business day prior to the consummation of the Merger (the “Domestication”). As more fully described elsewhere in this proxy statement/prospectus/information statement, you will be asked to consider and vote upon a proposal to approve the Domestication (the “Domestication Proposal”). In connection with the consummation of the Domestication, APAC will change its name to “OmniAb, Inc.” (APAC, following the Domestication, is sometimes referred to in the proxy statement/prospectus/information statement as “New OmniAb”);

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As a result of and upon the effective time of the Domestication, (1) each then issued and outstanding Class A ordinary share, par value $0.0001 per share, of APAC (the “APAC Class A Ordinary Shares”), will convert automatically, on a one-for-one basis, into a share of common stock, par value $0.0001 per share, of New OmniAb (the “New OmniAb Common Stock”), (2) each then issued and outstanding Class B ordinary share, par value $0.0001 per share, of APAC (the “APAC Class B Ordinary Shares”) will convert automatically, on a one-for-one basis, into a share of New OmniAb Common Stock, (3) each then issued and outstanding warrant of APAC (the “APAC Warrants”) will convert automatically into a warrant to acquire one share of New OmniAb Common Stock (the “New OmniAb Warrants”) pursuant to the Warrant Agreement, dated August 9, 2021 (the “Warrant Agreement”), by and between APAC and Continental Stock Transfer & Trust Company (“Continental”), a New York corporation, as warrant agent, and (4) each then issued and outstanding unit of APAC (the “APAC Units”), will separate and convert automatically into one share of New OmniAb Common Stock and one-third of one New OmniAb Warrant. As used in this proxy statement/prospectus/information statement, “public shares” shall mean the APAC Class A Ordinary Shares (including those that underlie the APAC Units) that were issued pursuant to APAC’s initial public offering and the shares of New OmniAb Common Stock issued as a matter of law upon the conversion thereof on the effective date of the Domestication, as applicable.

For further details, see “Shareholder Proposal No. 2 — The Domestication Proposal.”

Organizational Documents Proposal

APAC will also ask its shareholders to approve a proposal to approve and adopt the proposed certificate of incorporation and bylaws of New OmniAb in connection with the Domestication.

For further details, see “Shareholder Proposal No. 3 — The Organizational Documents Proposal.”

Non-Binding Governance Proposals

APAC’s shareholders are also being asked to consider and vote upon proposals to approve, on a non-binding advisory basis, certain material differences between APAC’s Amended and Restated Memorandum and Articles of Association (as it may be amended from time to time, the “Cayman Constitutional Documents”) and the proposed certificate of incorporation and bylaws of New OmniAb, presented separately in accordance with the United States Securities and Exchange Commission’s requirements.

The Proposed Organizational Documents differ in certain material respects from the Cayman Constitutional Documents and APAC encourages shareholders to carefully review the information set out in the sections entitled “Shareholder Proposal No. 3 — The Organizational Documents Proposal,” “Shareholder Proposal No. 4 — The Non-Binding Governance Proposals,” the Cayman Constitutional Documents of APAC, attached hereto as Annex J and the Proposed Organizational Documents of New OmniAb, attached hereto as Annex H and Annex I.

Stock Issuance Proposal

APAC’s shareholders are also being asked to approve a proposal for the purposes of complying with the applicable provisions of Nasdaq Rule 5635, the issuance of shares of New OmniAb Common Stock in connection with the Domestication, the Forward Purchase, the Redemption Backstop and the Merger.

For additional information, see “Shareholder Proposal No. 5 — The Stock Issuance Proposal.”

Incentive Plan Proposal

APAC’s shareholders are also being asked to approve a proposal for the adoption by New OmniAb of the OmniAb, Inc. 2022 Incentive Award Plan.

For additional information, see “Shareholder Proposal No. 6 — Incentive Plan Proposal.”

ESPP Proposal

APAC’s shareholders are also being asked to approve a proposal for the adoption by New OmniAb of the OmniAb, Inc. 2022 Employee Stock Purchase Plan.

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For additional information, see “Shareholder Proposal No. 7 — ESPP Proposal.”

Director Election Proposal

APAC’s shareholders are also being asked to approve a proposal to elect seven directors to the New OmniAb Board effective as of the closing of the Merger as contemplated by the Merger Agreement.

For additional information on the proposed directors, see “Shareholder Proposal No. 8 — The Director Election Proposal.”

Adjournment Proposal

APAC’s shareholders are also being asked to approve a proposal for the adjournment of the extraordinary general meeting to a later date or dates, if necessary, to permit further solicitation of proxies in the event that there are not sufficient votes to constitute a quorum or approve and adopt any one or more of the foregoing proposals at the extraordinary general meeting.

For additional information, see “Shareholder Proposal No. 9 — Adjournment Proposal.”

The APAC Boards’ Reasons for the Business Combination

APAC was incorporated for the purpose of effecting a merger, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses.

In evaluating the Business Combination, the APAC Board consulted with APAC’s management and legal and other advisors and considered a number of factors. In particular, the APAC Board considered, among other things, the following factors, although not weighted or in any order of significance:

Due Diligence. APAC and certain of its advisors conducted a diligence review of OmniAb and its business, including review of relevant documentation and discussions with OmniAb’s management and OmniAb’s financial, legal and other advisors.

Other Alternatives. After a review of other business combination opportunities reasonably available to APAC, the APAC Board believes that the proposed Business Combination represents the best potential business combination for APAC and the most attractive opportunity for APAC’s shareholders based upon the process utilized to evaluate and assess other potential acquisition targets, and that such process has not presented a better alternative.

Negotiated Transaction. The financial and other terms and condition of the Merger Agreement are, in the view of the APAC Board, reasonable and were the product of arm’s length negotiations between APAC and Ligand and its advisors.

For a more complete description of the APAC Boards’ reasons for approving the Business Combination, including other factors and risks considered by the APAC Board, see the section entitled “Shareholder Proposal No. 1 — The Business Combination Proposal — The APAC Boards’ Reasons for the Business Combination.”

The Ligand Board’s Reasons for the Business Combination

The Ligand Board believes that the separation of Ligand’s OmniAb Business from the remainder of its businesses through the Business Combination would be in the best interests of Ligand and its stockholders, including that the Business Combination will:

•

allow each of Ligand and OmniAb to pursue its own operational and strategic priorities and more quickly respond to trends, developments and opportunities in its respective markets;

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result in a tax-efficient separation of the OmniAb Business from Ligand’s other businesses;

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provide capital to support the growth of the OmniAb Business and the OmniAb platform technology;

•

create two separate and distinct management teams focused on each business’s unique strategic priorities, target markets and corporate development opportunities;

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•

give each business opportunity and flexibility by pursuing its own investment, capital allocation and growth strategies consistent with its long-term objectives;

•

allow investors to separately value each business based on the unique merits, performance and future prospects of each business, providing investors with two distinct investment opportunities;

•

enhance the ability of each business to attract and retain qualified management and to better align incentive-based compensation with the performance of each separate business;

•

give each of OmniAb and Ligand its own equity currency for use in connection with acquisitions; and

•

prior to the earlier of (i) 180 days after the date of the Merger Agreement or (ii) this S-4 registration statement being declared effective by the SEC, allow Ligand to respond to certain alternative transaction proposals and terminate the Merger Agreement, subject to payment of a termination fee to APAC, to accept an alternative proposal under certain circumstances.

The Ligand Board also considered potentially negative factors in evaluating the Business Combination, including the risks identified and discussed in the section entitled “Shareholder Proposal No. 1 — The Business Combination Proposal — The Ligand Board’s Reasons for the Business Combination” and “Risk Factors.” The Ligand Board concluded that the potential benefits of the Business Combination outweighed these factors.

Related Agreements

This section describes certain additional agreements entered into or to be entered into pursuant to the Merger Agreement. For additional information, see “Shareholder Proposal No. 1 — The Business Combination Proposal — Summary of the Separation Agreement” and “— Summary of the Ancillary Agreements.”

Separation Agreement

On March 23, 2022, in connection with the execution of the Merger Agreement, Ligand, OmniAb and APAC entered into the Separation Agreement which sets forth the principal actions to be taken in connection with the Separation. The Separation Agreement identifies assets to be transferred, liabilities to be assumed and contracts to be assigned to each of Ligand and OmniAb as part of the internal reorganization described therein and requires the Ligand Contribution to be made to OmniAb. The Separation Agreement also sets forth other agreements that govern certain aspects of OmniAb’s relationship with Ligand following the Business Combination. Pursuant to the Separation Agreement, OmniAb will issue additional shares of OmniAb Common Stock to Ligand. Ligand will then distribute on a pro rata basis all of the outstanding shares of OmniAb Common Stock to the holders of Ligand Common Stock as of the Ligand Record Date set for the Distribution by delivering to the distribution agent a book-entry authorization representing the shares of OmniAb Common Stock being distributed for the account of Ligand’s stockholders. The distribution agent will hold such book-entry shares for the account of OmniAb’s stockholders (as of immediately after consummation of the Distribution) pending the Merger. The Separation Agreement is attached to this proxy statement/prospectus/information statement as Annex B.

Employee Matters Agreement

On March 23, 2022, in connection with the execution of the Merger Agreement, APAC, Ligand, OmniAb and Merger Sub entered into the Employee Matters Agreement, which sets forth the terms and conditions of certain employee-related matters in connection with the transaction, including allocation of benefit plan assets and liabilities between Ligand and OmniAb, treatment of incentive equity awards in the Distribution and the Business Combination and related covenants and commitments of the parties. On August 18, 2022, the parties entered into an Amended and Restated Employee Matters Agreement in order to update the treatment of certain incentive equity awards in the Distribution and the Business Combination. Pursuant to the Employee Matters Agreement (as amended), (i) each existing Ligand equity award granted prior to March 2, 2022, with certain limited exceptions, will be split into (A) a new Ligand equity award and (B) a new OmniAb Equity Award, with any intrinsic value in the original Ligand equity award split between such awards based on the relative values of Ligand and OmniAb at the time of the

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Distribution, and (ii) each existing Ligand equity award granted on or after March 2, 2022 will be converted into either (A) if the holder will be a Ligand service provider following the Distribution, an adjusted Ligand equity award, or (B) if the holder will be an OmniAb service provider following the Distribution, a new OmniAb Equity Award, with the intrinsic value of such adjusted or converted award equal to the intrinsic value in the original Ligand equity award based on the relative values of Ligand and OmniAb at the time of the Distribution. The Employee Matters Agreement is attached to this proxy statement/prospectus/information statement as Annex K.

Sponsor Insider Agreement

On March 23, 2022, in connection with the execution of the Merger Agreement, OmniAb, the Sponsor and the directors and officers of APAC (the “Insiders”) entered into the Sponsor Insider Agreement, pursuant to which, among other things, the Insiders agreed to vote any APAC securities held by them to approve the Business Combination Proposal and the other APAC shareholder matters required pursuant to the Merger Agreement, and not to seek redemption of any of their APAC securities in connection with the consummation of the Business Combination. Pursuant to the Sponsor Insider Agreement, the Sponsor also agreed to subject up to all 1,916,667 Sponsor Earnout Shares to forfeiture if an applicable Sponsor Triggering Event has not occurred with respect to such Sponsor Earnout Shares during the period from the date of the Closing to and including the fifth anniversary of the date of the Closing. The Sponsor Insider Agreement is attached to this proxy statement/prospectus/information statement as Annex C.

Amended & Restated Forward Purchase Agreement

On March 23, 2022, in connection with the execution of the Merger Agreement, APAC entered into the A&R FPA with the Sponsor and OmniAb. Pursuant to the A&R FPA, APAC has agreed that, in connection with the consummation of the Business Combination, it will issue and sell to the Sponsor 1,500,000 shares of New OmniAb Common Stock and warrants to acquire 1,666,667 shares of New OmniAb Common Stock for an aggregate purchase price of $15,000,000 in the Forward Purchase. In addition to the Forward Purchase, the Sponsor has agreed to purchase up to an additional 10,000,000 shares of New OmniAb Common Stock and up to an additional 1,666,667 APAC warrants in the Redemption Backstop, for an aggregate additional purchase price of up to $100,000,000 in order to backstop shareholder redemptions to the extent such redemptions would result in the cash proceeds to be available to the combined company following the Business Combination from APAC’s trust account to be less than $100,000,000. The A&R FPA also provides that in the event the Merger Agreement is terminated by Ligand under circumstances in which the Termination Fee would be payable under the Merger Agreement, Ligand shall pay the Sponsor a termination fee of $12,500,000 in connection therewith. The A&R FPA is attached to this proxy statement/prospectus/information statement as Annex D.

Amended & Restated Registration and Stockholder Rights Agreement

Concurrently with the completion of the Business Combination, APAC, Sponsor, the existing holders party to the original Registration and Stockholder Rights Agreement, dated August 9, 2021 (the “Original Registration Rights Agreement”), and the new holders to become party to the A&R Registration Rights Agreement, will enter into an Amended & Restated Registration and Stockholder Rights Agreement, the form of which is attached to this proxy statement/prospectus/information statement as Annex G (the “A&R Registration Rights Agreement”). The Original Registration Rights Agreement will be amended to, among other things, require APAC to use commercially reasonable efforts to, within thirty (30) days after the Closing, file a registration statement on Form S-1 to permit the public resale of all of the Registrable Securities (as defined in the A&R Registration Rights Agreement) held by the holders from time to time as permitted by Rule 415 under the Securities Act, and to provide certain equityholders of OmniAb as of immediately prior to the Closing of the Business Combination with customary registration rights.

Tax Matters Agreement

Prior to the Distribution, APAC, OmniAb, and Ligand will enter into the Tax Matters Agreement that will govern each party’s respective rights, responsibilities and obligations with respect to tax liabilities and

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benefits, tax attributes, the preparation and filing of tax returns, the control of audits and other tax proceedings and certain other matters regarding taxes.

In general, APAC and OmniAb will be liable for all U.S. federal, state, local and foreign taxes (and any related interest, penalties or audit adjustments) that are (i) imposed with respect to tax returns that include both OmniAb and Ligand, to the extent such taxes are attributable to OmniAb or the OmniAb Business, or (ii) imposed with respect to tax returns that include OmniAb but not Ligand, in each case, for tax periods (or portions thereof) beginning after the Distribution.

Notwithstanding the foregoing, APAC and OmniAb may be liable for certain taxes resulting from the restructuring transactions undertaken to effectuate the Distribution.

The Distribution, together with certain related transactions, is intended to qualify as a reorganization under Sections 355 and 368(a)(1)(D) of the Code. Pursuant to the Tax Matters Agreement, taxes incurred by Ligand, APAC or OmniAb relating to or arising out of the failure of the intended tax treatment will generally be shared equally by Ligand, on the one hand, and APAC and OmniAb, on the other hand. If, however, such failure is attributable to certain acts or omissions by APAC or OmniAb, inaccuracies, misrepresentations or misstatements relating to APAC or OmniAb or certain events involving the stock of APAC or OmniAb or assets of OmniAb, APAC and OmniAb will generally bear all such taxes. Under certain circumstances, including if the failure is attributable to Ligand or an event involving Ligand’s stock or assets, Ligand will bear all such taxes.

The Tax Matters Agreement will require APAC and OmniAb to comply with the representations made in the materials submitted to legal counsel in connection with the Distribution Tax Opinion that Ligand expects to receive regarding the intended tax treatment of the Distribution and certain related transactions. The Tax Matters Agreement will also restrict OmniAb’s and APAC’s ability to take or fail to take any action if such action or failure to act could reasonably be expected to adversely affect the intended tax treatment. In particular, in the two years following the Distribution, APAC and OmniAb will be subject to certain restrictions, generally including being prevented from (i) entering into any transaction which could, when combined with other transactions (including the Merger), result in a 45% or greater change in ownership of APAC’s or OmniAb’s equity as part of a plan or series of related transactions that includes the Distribution, (ii) ceasing the active conduct of certain of OmniAb’s businesses, (iii) voluntarily dissolving or liquidating APAC or OmniAb and (iv) causing, permitting, or agreeing to the sale, transfer, or disposal of assets of OmniAb that, in the aggregate, constitute more than 30% of the consolidated gross assets of OmniAb, in each case, unless OmniAb obtains a private letter ruling from the IRS, an unqualified opinion of a nationally recognized tax advisor that such action will not cause a failure of the intended tax treatment, or Ligand consents to the undertaking of such action.

Notwithstanding receipt of such ruling, opinion or consent, in the event that such action causes a failure of the intended tax treatment, APAC and OmniAb could be responsible for all taxes arising therefrom.

APAC’s and OmniAb’s obligations under the Tax Matters Agreement are not limited in amount or subject to any cap.

Transition Services Agreements

In connection with the Separation, OmniAb and Ligand will enter into two Transition Services Agreements pursuant to which Ligand and its affiliates and OmniAb and its affiliates will provide to each other various non-scientific and non-technical services set forth in the applicable Transition Services Agreement, which services are of the type that OmniAb and Ligand provided to, and received from, each other prior to the Separation. The fees for each of the transition services are set forth in the applicable Transition Services Agreement as a flat monthly fee, and the receiving party will reimburse the providing party for all reasonable out-of-pocket costs and expenses that the providing party incurs in connection with providing the transition services. Each of the Transition Services Agreements will terminate on the expiration of the term of the last service provided under it, unless earlier terminated by the receiving party with prior written notice, by either party in the event of an uncured material breach by the other party or its applicable affiliates, upon bankruptcy or insolvency of the other party, or by mutual agreement of the parties. The transition services are generally expected to last up to one year and the receiving party for a particular service

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may terminate such service prior to the scheduled expiration date with prior written notice. OmniAb does not anticipate that its net costs associated with the Transition Services Agreements will be materially different than the historical costs that have been allocated by Ligand to OmniAb related to these same services.

Ownership of APAC following Business Combination

As of the date of this proxy statement/prospectus/information statement, there are 28,750,000 ordinary shares of APAC issued and outstanding, which include the 5,750,000 founder shares held by the Sponsor (including APAC’s directors) and the 23,000,000 public shares. As of the date of this proxy statement/prospectus/information statement, there are outstanding an aggregate of 15,900,000 APAC Warrants, which include the 8,233,333 APAC Private Placement Warrants held by the Sponsor and the 7,666,667 APAC Public Warrants. Each whole warrant entitles the holder thereof to purchase one APAC Class A Ordinary Share and, following the Domestication, will entitle the holder thereof to purchase one share of New OmniAb Common Stock. Therefore, as of the date of this proxy statement/prospectus/information statement (without giving effect to the Business Combination), the APAC fully diluted share capital would be 44,650,000. It is anticipated that, following the Business Combination, (1) APAC’s public shareholders are expected to own approximately 18.0% of the outstanding shares of New OmniAb Common Stock, (2) OmniAb stockholders (without taking into account any public shares held by OmniAb stockholders prior to the consummation of the Business Combination) are expected to own approximately 76.3% of the outstanding shares of New OmniAb Common Stock and (3) the Sponsor and related parties are expected to collectively own approximately 5.7% of the outstanding shares of New OmniAb Common Stock. These percentages (i) assume (a) that no public shareholders exercise their redemption rights in connection with the Business Combination, (b) that New OmniAb issues 97,731,592 shares of New OmniAb Common Stock to former stockholders of OmniAb and former holders of OmniAb Equity Awards as of immediately prior to the Effective Time and (c) that New OmniAb issues 1,500,000 shares of New OmniAb Common Stock to the Sponsor pursuant to the Forward Purchase, (ii) exclude all New OmniAb Options that may be exercisable for shares of New OmniAb Common Stock, New OmniAb RSUs and New OmniAb PSUs, (iii) include the Sponsor Earnout Shares and the OmniAb Earnout Shares (as defined in the Merger Agreement) and (iv) exclude the impact of any New OmniAb Warrants that will be outstanding following the Business Combination (we refer to this set of assumptions as the “no redemption scenario”). If the actual facts are different from the no redemption scenario, the percentage ownership of New OmniAb held by such constituencies will be different.

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	Share Ownership in New OmniAb
	No Redemption Scenario				50% Redemption Scenario(1)				Maximum Redemption Scenario(2)
	Number of Shares		Percentage of Outstanding Shares		Number of Shares		Percentage of Outstanding Shares		Number of Shares		Percentage of Outstanding Shares
APAC’s public shareholders		23,000,000		18.0%		11,500,000		9.9%		—		0.0%
Sponsor and related parties(3)(4)(6)		7,250,000		5.7%		7,250,000		6.2%		17,250,000		15.0%
OmniAb’s (Ligand’s) stockholders (5)(6)		97,731,592		76.3%		97,731,592		83.9%		97,731,592		85.0%
Total(7)(8)		127,981,592		100.0%		116,481,592		100.0%		114,981,592		100.0%

(1)

Assumes redemptions of 11,500,000 APAC Class A Ordinary Shares in connection with the Business Combination.

(2)

Assumes redemptions of 23,000,000 APAC Class A Ordinary Shares in connection with the Business Combination.

(3)

(4)

Pursuant to the A&R FPA, includes 1,500,000 shares of New OmniAb Common Stock purchased by the Sponsor in the Forward Purchase in the no redemption, 50% redemption and maximum redemption scenarios and an additional 10,000,000 shares of New OmniAb Common Stock purchased by the Sponsor in the Redemption Backstop in the maximum redemption scenario.

(5)

Includes 15,000,000 OmniAb Earnout Shares issued to former OmniAb stockholders and former OmniAb Equity Award holders, as, during the Earnout Period, OmniAb Earnout Shares are entitled to exercise the voting rights carried by such Earnout Shares and receive any dividends or other distributions in respect of such OmniAb Earnout Shares. For a description of the assumptions used in calculating the number of shares to be owned by OmniAb’s (Ligand’s) stockholders, see “Shareholder Proposal No. 1 — The Business Combination Proposal — Ownership of APAC after the Business Combination.”

(6)

The table below sets forth the share ownership in New OmniAb assuming that the Sponsor Earnout Shares and the OmniAb Earnout Shares are forfeited according to their terms:

	Share Ownership in New OmniAb
	No Redemption Scenario				50% Redemption Scenario				Maximum Redemption Scenario
	Number of Shares		Percentage of Outstanding Shares		Number of Shares		Percentage of Outstanding Shares		Number of Shares		Percentage of Outstanding Shares
APAC’s public shareholders		23,000,000		20.7%		11,500,000		11.6%		—		0.0%
Sponsor and related parties		5,333,333		4.8%		5,333,333		5.4%		16,052,083		16.3%
OmniAb’s (Ligand’s) stockholders		82,731,592		74.5%		82,731,592		83.0%		82,731,592		83.8%
Total		111,064,925		100.0%		99,564,925		100.0%		98,783,675		100.0%

(7)

The table excludes the following:

•

13,587,254 unexercised OmniAb Options;

•

1,402,039 OmniAb RSUs and OmniAb PSUs;

•

7,666,667 unexercised APAC Public Warrants;

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•

8,233,333 unexercised APAC Private Placement Warrants;

•

1,666,667 unexercised APAC Warrants issued in the Forward Purchase;

•

1,666,667 unexercised APAC Warrants issued in the Redemption Backstop in the maximum redemption scenario; and

•

500,000 unexercised APAC Private Placement Warrants issuable pursuant to the convertible promissory note.

(8)

If all of the Sponsor’s APAC Warrants are exercised, which include the 8,233,333 APAC Private Placement Warrants, the 1,666,667 APAC Warrants issued in the Forward Purchase the 1,666,667 APAC Warrants issued in the Redemption Backstop in the maximum redemption scenario, and the 500,000 unexercised APAC Private Placement Warrants issuable pursuant to the convertible promissory note, Sponsor would own: (1) approximately 12.8% of the shares of New OmniAb in the no redemption scenario, (2) approximately 13.9% of the shares of New OmniAb in the 50% redemption scenario or (3) approximately 23.1% of the shares of New OmniAb in the maximum redemptions scenario.

	Share Ownership in New OmniAb(1)
	No Redemptions Scenario				50% Redemptions Scenario				100% Redemptions Scenario
Additional Dilution Sources	Number of Underlying Shares		Percentage of then Outstanding Shares		Number of Underlying Shares		Percentage of then Outstanding Shares		Number of Underlying Shares		Percentage of then Outstanding Shares
APAC Warrants
APAC Public Warrants(2)		7,666,667		5.7%		7,666,667		6.2%		7,666,667		6.3%
APAC Private Placement Warrants(3)		8,233,333		6.0%		8,233,333		6.6%		8,233,333		6.7%
APAC Warrants issued in the Forward Purchase(4)		1,666,667		1.3%		1,666,667		1.4%		1,666,667		1.4%
APAC Warrants issued in the Redemption Backstop(5)		0		0.0%		0		0.0%		1,666,667		1.4%
APAC Private Placement Warrants Issuable Pursuant to Convertible Promissory Note(6)		500,000		0.4%		500,000		0.4%		500,000		0.4%
OmniAb Prior Plans
OmniAb Options(7)		13,587,254		9.6%		13,587,254		10.4%		13,587,254		10.6%
OmniAb RSUs and OmniAb PSUs(8)		1,402,039		1.1%		1,402,039		1.2%		1,402,039		1.2%
New OmniAb Proposed Plans
2022 Plan(9)		18,235,000		12.5%		16,625,000		12.5%		16,415,000		12.5%
ESPP(10)		1,953,750		1.5%		1,781,250		1.5%		1,758,750		1.5%
Total Additional Dilutive Sources(11)		53,244,710		29.4%		51,462,210		30.6%		52,896,377		31.5%

(1)

Percentages in this table assume that the dilutive shares are added to the outstanding shares as of immediately following the Closing in the respective redemption scenario.

(2)

This row assumes exercise of all APAC Public Warrants to purchase 7,666,667 shares of New OmniAb Common Stock. Percentages in this row represent (a) the shares of New OmniAb Common Stock

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underlying the APAC Public Warrants divided by (b) (i) the outstanding shares as of the closing in the respective redemption scenario plus (ii) 7,666,667 shares of New OmniAb Common Stock underlying the APAC Public Warrants.

(3)

(4)

(5)

This row assumes (solely in the case of the maximum redemption scenario) exercise of all APAC Warrants issued in the Redemption Backstop to purchase 1,666,667 shares of New OmniAb Common Stock. Percentages in this row represent (a) the shares of New OmniAb Common Stock underlying the APAC Warrants purchased in the Redemption Backstop divided by (b) (i) the outstanding shares as of immediately following the Closing in the applicable redemption scenario plus (ii) 1,666,667 shares of New OmniAb Common Stock underlying the APAC Warrants purchased in the Redemption Backstop (in the maximum redemption scenario).

(6)

(7)

(8)

(9)

(10)

This row assumes the issuance of a number of shares equal to 1.5% of the fully diluted shares of New OmniAb Common Stock (calculated as specifically provided under the ESPP) to be outstanding

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immediately following the Closing reserved for issuance under the ESPP. Percentages in this row represent (a) the shares of New OmniAb Common Stock reserved and issuable under the ESPP divided by (b) the sum of (i) the outstanding shares as of immediately following the Closing in the applicable redemption scenario and (ii) the shares of New OmniAb Common Stock reserved and issuable under the ESPP. For a description of the assumptions used in calculating the number of shares reserved under the proposed ESPP, see “Shareholder Proposal No. 7 — ESPP Proposal.”

(11)

In addition to the changes in percentage ownerships depicted above, variation in the levels of redemption will impact the dilutive effect of certain equity issuances related to the Business Combination. As illustrated in the table below, certain equity issuances may have a dilutive effect on the per share value of New OmniAb. See the section entitled “Risk Factors — Risks Related to Redemption” for additional information.

	Share Ownership in New OmniAb
	No Redemptions Scenario					50% Redemptions Scenario(1)					100% Redemptions Scenario(2)
	Number of Shares		Value per Share(3)			Number of Shares		Value per Share(3)			Number of Shares		Value per Share(3)
Base Scenario(4)		127,981,592		$	10.27		116,481,592		$	10.27		114,981,592		$	10.25
Excluding Sponsor Earnout Shares and OmniAb Earnout Shares(5)		111,064,925		$	11.83		99,564,925		$	12.01		98,783,675		$	11.93
Assuming Exercise of APAC Public Warrants(6)		135,648,259		$	10.34		124,148,259		$	10.35		122,648,259		$	10.32
Assuming Exercise of APAC Private Placement Warrants(7)		136,214,925		$	10.34		124,714,925		$	10.35		123,214,925		$	10.33
Assuming Exercise of APAC Warrants issued in the Forward Purchase(8)		129,648,259		$	10.29		118,148,259		$	10.29		116,648,259		$	10.26
Assuming Exercise of APAC Warrants issued in the Redemption Backstop(9)		127,981,592		$	10.27		116,481,592		$	10.27		116,648,259		$	10.26
Assuming Exercise of APAC Private Placement Warrants Issuable Pursuant to Convertible Promissory Note(10)		128,481,592		$

	Page
REFERENCES TO ADDITIONAL INFORMATION		6
TRADEMARKS		7
SELECTED DEFINITIONS		8
CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS		14
QUESTIONS AND ANSWERS		16
SUMMARY OF THE PROXY STATEMENT/PROSPECTUS/INFORMATION STATEMENT		45
MARKET PRICE AND DIVIDEND INFORMATION		76
UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION OF APAC AND OMNIAB		78
RISK FACTORS		92
EXTRAORDINARY GENERAL MEETING OF APAC		160
SHAREHOLDER PROPOSAL NO. 1 – THE BUSINESS COMBINATION PROPOSAL		167
SHAREHOLDER PROPOSAL NO. 2 – THE DOMESTICATION PROPOSAL		236
SHAREHOLDER PROPOSAL NO. 3 – THE ORGANIZATIONAL DOCUMENTS PROPOSAL		238
SHAREHOLDER PROPOSAL NO. 4 – THE NON-BINDING GOVERNANCE PROPOSAL		241
SHAREHOLDER PROPOSAL NO. 5 – THE STOCK ISSUANCE PROPOSAL		245
SHAREHOLDER PROPOSAL NO. 6 – THE INCENTIVE PLAN PROPOSAL		248
SHAREHOLDER PROPOSAL NO. 7 – THE ESPP PROPOSAL		253
SHAREHOLDER PROPOSAL NO. 8 – THE DIRECTOR ELECTION PROPOSAL		258
SHAREHOLDER PROPOSAL NO. 9 – THE ADJOURNMENT PROPOSAL		260
MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES TO APAC SHAREHOLDERS		261
MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES TO LIGAND STOCKHOLDERS OF THE DISTRIBUTION AND MERGER		275
INFORMATION ABOUT APAC AND MERGER SUB		280
APAC MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS		285
MANAGEMENT OF APAC		293
INFORMATION ABOUT LIGAND		300
INFORMATION ABOUT THE OMNIAB BUSINESS		301
OMNIAB MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS		337
EXECUTIVE AND DIRECTOR COMPENSATION OF OMNIAB		356
MANAGEMENT OF NEW OMNIAB AFTER THE BUSINESS COMBINATION		373
BENEFICIAL OWNERSHIP OF SECURITIES		381
CERTAIN RELATIONSHIPS AND RELATED PERSON TRANSACTIONS		386
SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT OF OMNIAB		392
THE SEPARATION AND DISTRIBUTION		394
DESCRIPTION OF COMBINED COMPANY SECURITIES		395
COMPARISON OF CORPORATE GOVERNANCE AND SHAREHOLDER RIGHTS		400
SECURITIES ACT RESTRICTIONS ON RESALE OF COMBINED COMPANY’S SECURITIES		411

	Page
Dissenters’ Rights and Appraisal Rights		412
SUBMISSION OF SHAREHOLDER PROPOSALS		413
FUTURE SHAREHOLDER PROPOSALS		414
DELIVERY OF DOCUMENTS TO SHAREHOLDERS/HOUSEHOLDING		415
OTHER SHAREHOLDER COMMUNICATIONS		416
LEGAL MATTERS		416
EXPERTS		416
WHERE YOU CAN FIND MORE INFORMATION		417
INDEX TO FINANCIAL STATEMENTS		F-1
INDEX TO COMBINED FINANCIAL STATEMENTS		F-1
ANNEXES		A-1
INFORMATION NOT REQUIRED IN PROSPECTUS		II-0