SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 13D/A

(Amendment No. 2)

(Rule 13d-101)

Under the Securities Exchange Act of 1934

Hampden Bancorp, Inc.

(Name of Issuer)

Common Stock, $0.01 par value

(Title of Class of Securities)

40867E107

(CUSIP Number)

Clover Partners, L.P.

100 Crescent Court, Suite 575

Dallas, TX 75201

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

- with copies to -

Phillip M. Goldberg

Foley & Lardner LLP

321 North Clark Street

Chicago, Illinois 60610

(312) 832-4549

May 1, 2013

(Date of event which requires filing of this statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition which is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(b)(3) or (4), check the following box.  x

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934, as amended (the “Act”), or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act.

SCHEDULE 13D/A

This Second Amended Schedule 13D (this “Schedule 13D/A”) amends and restates the Schedule 13D initially filed with the Securities and Exchange Commission on August 22, 2012 and is being filed on behalf of MHC Mutual Conversion Fund, L.P., a Texas limited partnership (the “Fund”), Clover Partners, L.P., a Texas limited partnership and the general partner of the Fund (the “GP”), Clover Investments, L.L.C., a Texas limited liability company and the general partner of the GP (“Clover”), and Michael C. Mewhinney, the principal of Clover (collectively, the “MHC Mutual Conversion Fund Group”), relating to common stock ($0.01 par value) (the “Common Stock”) of Hampden Bancorp, Inc., a Delaware corporation (the “Issuer”).

With regard to the MHC Mutual Conversion Fund Group, this Schedule 13D/A relates to Common Stock of the Issuer purchased by the GP through the account of the Fund. The Fund may direct the vote and disposition of the 377,732 shares of Common Stock it holds directly. The GP serves as the investment adviser and general partner to the Fund and may direct the vote and disposition of the 377,732 shares of Common Stock held by the Fund. Clover serves as the general partner of the GP and may direct the GP to direct the vote and disposition of the 377,732 shares of Common Stock held by the Fund. As the manager of Clover, Mewhinney may direct the vote and disposition of the 377,732 shares of Common Stock held by the Fund. The MHC Mutual Conversion Fund Group expressly disclaims beneficial ownership of securities held by Mr. Guerry and Mr. Base. The securities reported herein as being beneficially owned by the MHC Mutual Conversion Fund Group do not include any securities held by Mr. Guerry or Mr. Base.

By virtue of Johnny Guerry and Garold R. Base agreeing to serve as nominees for election to the Issuer’s Board of Directors in connection with the nomination of director candidates by the Fund, Mr. Guerry and Mr. Base may be deemed to constitute a “group” with the MHC Mutual Conversion Fund Group for purposes of Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Mr. Guerry and Mr. Base expressly disclaim beneficial ownership of securities held by the MHC Mutual Conversion Fund Group and by each other. The securities reported herein (if any) as being beneficially owned by Mr. Guerry or Mr. Base do not include any securities held by each other or by any member of the MHC Mutual Conversion Fund Group.

(a) With regard to the MHC Mutual Conversion Fund Group, this Schedule 13D/A is jointly filed by the Fund, the GP, Clover and Mr. Mewhinney. Because Mr.

Mewhinney is the manager of Clover, which is the general partner of the GP (with Mr. Mewhinney, the Fund and Clover hereinafter referred to as the “Controlling Persons”), the Controlling Persons may be deemed, pursuant to Rule 13d-3 of the Securities Exchange Act of 1934, as amended (the “Act”), to be the beneficial owners of all of the Common Stock held by the Fund.

Each of the persons identified in this Schedule 13D/A is referred to as a “Reporting Person” and, collectively, as the “Reporting Persons.” Each of the Reporting Persons is a party to that certain Joint Filing Agreement attached hereto as Exhibit 1. While Mr. Guerry and Mr. Base may be deemed to constitute a “group” with the MHC Mutual Conversion Fund Group for purposes of Section 13(d)(3) of the Exchange Act, due to Mr. Guerry and Mr. Base agreeing to serve as nominees for election to the Issuer’s Board of Directors in connection with the nomination of director candidates by the MHC Mutual Conversion Fund Group, neither Mr. Guerry nor Mr. Base is, and will not become, a party to any agreement, arrangement or understanding with, and has not given any commitment or assurance to, the MHC Mutual Conversion Fund Group as to how he will, if elected as a director of the Issuer, act or vote on any issue or question.

The Reporting Persons are filing this Schedule 13D/A jointly, as they may be considered a “group” under Section 13(d)(3) of the Act. However, neither the fact of this filing nor anything contained herein shall be deemed to be an admission by the Reporting Persons that such a group exists.

(b) The principal place of business for each of the Reporting Persons (other than Mr. Base) is 100 Crescent Court, Suite 575, Dallas, TX 75201. The principal place of business for Mr. Base is 2100 Crown Knoll Ln., Plano, Texas 75093.

(c) The principal occupation of Mr. Mewhinney is serving as the managing member of Clover. The principal business of Clover is acting as the general partner of the GP. The principal business of the GP is investment management. The principal business of the Fund is investing in securities.

The principal occupation of Mr. Guerry is serving as a partner of Clover.

Mr. Base owns and operates his own consulting practice under the name Base & Associates.

(d) During the last five years, none of the Reporting Persons have been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

(e) During the last five years, none of the Reporting Persons have been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and, as a result of such proceeding, were or are subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

(f) The Fund, the GP and Clover are organized under the laws of the State of Texas. Mr. Mewhinney, Mr. Guerry and Mr. Base are each a citizen of the United States of America.

As of the date of this Schedule 13D/A, the Fund had invested $4,811,026.83 (inclusive of brokerage commissions) in Common Stock of the Issuer. The source of these funds was the working capital of the Fund.

As of the date of this Schedule 13D/A, Mr. Base had invested $34,469.27 (inclusive of brokerage commissions) in Common Stock of the Issuer. The source of these funds was personal investment capital.

The Reporting Persons purchased the Common Stock for investment purposes. The MHC Mutual Conversion Fund Group’s intent is to influence the policies of the Issuer and assert shareholder rights, with a goal of maximizing the value of the Common Stock.

Consistent with its investment purpose, the MHC Mutual Conversion Fund Group has engaged and will continue to engage in communications with one or more officers of the Issuer and/or one or more members of the board of directors of the Issuer (the “Board”), and/or one or more representatives of the Issuer regarding the Issuer, including, but not limited to its business, management, operations, assets, capitalization, financial condition, governance, strategy and future plans. The MHC Mutual Conversion Fund Group has discussed and will continue to discuss ideas that, if effectuated, may result in any of the following: a sale or transfer of a material amount of assets of the Issuer and/or changes in the board of directors or management of the Issuer.

The Reporting Persons may purchase, sell or transfer Common Stock beneficially owned by them from time to time in public transactions depending on economic considerations and, subject to the below, the results of such communications. Any such transactions may be effected at any time or from time to time subject to any applicable limitations imposed on the sale of the Common Stock by applicable law.

On October 17, 2012, the Reporting Persons sent a letter to the Board (the “Board Letter”) regarding the operations of the Issuer. A copy of the Board Letter is incorporated by reference into this Schedule 13D/A as Exhibit 2 hereto (it is incorporated by reference to Exhibit 2 filed with Amendment No. 1 to this Schedule 13D/A, as filed on October 17, 2012).

On May 1, 2013, the Fund submitted notice to the Issuer of its intent to nominate Mr. Guerry and Mr. Base as nominees for election as directors, on the WHITE proxy card, at the Issuer’s 2013 Annual Shareholder Meeting. A copy of the nomination letter is attached as Exhibit 3 hereto.

Except to the extent the foregoing may be deemed a plan or proposal, the Reporting Persons have no plans or proposals which relate to, or could result in, any of the matters referred to in paragraphs (a) through (j), inclusive, of the instructions to Item 4 of the Schedule 13D. The Reporting Persons may, at any time and from time to time, review or reconsider their position and/or change their purpose and/or formulate plans or proposals with respect thereto.

(a) - (b) The MHC Mutual Conversion Fund Group beneficially owns 377,732 shares of Common Stock, which represents 6.5% of the Issuer’s outstanding shares of Common Stock. The percentage of beneficial ownership of the Reporting Persons, as reported in this Schedule 13D/A, was calculated by dividing (i) the total number of shares of Common Stock beneficially owned by the MHC Mutual Conversion Fund Group as of May 1, 2013, as set forth in this Schedule 13D/A, by (ii) the 5,785,174, shares of Common Stock outstanding as of February 6, 2013, according to the Issuer’s Form 10-Q filed with the Securities and Exchange Commission on February 12, 2013.

The GP, in its capacity as investment manager and general partner to the Fund has power to vote the 377,732 shares of Common Stock and the power to dispose of the 377,732 shares of Common Stock held in the Fund. Clover, in its capacity as general partner of the GP and Mr. Mewhinney, as the managing member of Clover, may each be deemed to beneficially own the Common Stock held in the Fund.

Mr. Base beneficially owns 2,652 shares of the Common Stock, less than 1% of the Issuer’s outstanding shares of Common Stock.

(c) None of the Reporting Persons has effected any transactions in the Common Stock during the last sixty days.

The filing of this Schedule 13D/A shall not be construed as admission that the GP, Clover, or Mr. Mewhinney is for the purposes of Section 13(d) or 13(g) of the Act the beneficial owner of any of the 377,732 shares of Common Stock owned by the Fund. Pursuant to Rule 13d-4, the GP, Clover, and Mr. Mewhinney disclaim all such beneficial ownership.

(d) No person other than the Reporting Persons is known to have the right to receive, or the power to direct the receipt of dividends from, or proceeds from the sale of, the Common Stock.

(e) Not applicable.

With respect to the Fund, GP is entitled to (1) an allocation of a portion of profits, if any, and (2) a management fee based upon a percentage of total capital.

Messrs. Guerry and Base are indemnified by the Fund for liabilities they may incur in connection with the intended solicitation of proxies for use at the 2013 Annual Meeting of Shareholders of the Issuer. The Fund will also reimburse Messrs. Guerry and Base for expenses that they reasonably incur in connection with the intended solicitation of proxies for use at the 2013 Annual Meeting of Shareholders of the Issuer. Neither Mr. Guerry nor Mr. Base

is, and will not become, a party to any agreement, arrangement or understanding with, and has not given any commitment or assurance to, the Fund, each other or any other person as to how he, if elected as a director of the Issuer, will act or vote on any issue or question.

Other than the foregoing agreements and arrangements, and the Joint Filing Agreement, there are no contracts, arrangements, understandings or relationships among the persons named in Item 2 hereof and between such persons and any person with respect to any securities of the Issuer.

SIGNATURES

After reasonable inquiry and to the best of their knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated: May 1, 2013

Exhibit 1

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, the undersigned agree to the joint filing on behalf of each of them of a Statement on Schedule 13D (including any and all amendments thereto) with respect to the Common Stock, of Hampden Bancorp, Inc., and further agree that this Joint Filing Agreement shall be included as an Exhibit to such joint filings.

The undersigned further agree that each party hereto is responsible for the timely filing of such Statement on Schedule 13D/A and any amendments thereto, and for the accuracy and completeness of the information concerning such party contained therein; provided, however, that no party is responsible for the accuracy or completeness of the information concerning any other party, unless such party knows or has reason to believe that such information is inaccurate.

This Joint Filing Agreement may be signed in counterparts with the same effect as if the signature on each counterpart were upon the same instrument.

IN WITNESS WHEREOF, the undersigned have executed this Agreement as of May 1, 2013.

Exhibit 3

May 1, 2013

CERTIFIED MAIL RETURN RECEIPT REQUESTED AND OVERNIGHT DELIVERY

Attention: Corporate Secretary

Hampden Bancorp, Inc.

19 Harrison Avenue

Springfield, Massachusetts 01102

Ladies and Gentlemen:

This letter constitutes a notice of intent by MHC Mutual Conversion Fund, L.P. (the “Stockholder”) to nominate two persons for election as directors of Hampden Bancorp, Inc. (the “Company”) at the 2013 Annual Meeting of Stockholders of the Company, and to submit its nominees for election at such Annual Meeting. This notice is being provided to you pursuant to Section 6 of Article I of the Company’s Amended and Restated Bylaws, as amended to date, and is being submitted on behalf of the Stockholder by Johnny Guerry, a principal of Clover Investments, L.L.C., the general partner of the Stockholder.

The Stockholder hereby certifies that it is entitled to vote and beneficially owns 377,732 shares of the Company’s common stock, par value $0.01 per share (the “Common Stock”). Pursuant to the Schedule 13D filed by the Stockholder with the Securities and Exchange Commission, as amended to date, the Stockholder owns 6.5% of the total common shares outstanding. As documentary evidence of the Stockholder’s beneficial ownership, the Stockholder provides a letter of verification from the Stockholder’s broker, attached as Exhibit A hereto, showing that the Stockholder holds 377,732 shares of Common Stock (the Stockholder affirms that the documentary evidence of ownership enclosed herewith is a true and correct copy of what it purports to be).

By the fact of the Stockholder’s submission of this notice of intent to nominate and submit its nominee for election, it is the Stockholder’s understanding the Company will now generally be obligated under the federal securities laws to file a preliminary proxy statement and form of proxy with the United States Securities and Exchange Commission to allow the Commission to review and comment on such proxy materials.

The Stockholder hereby notifies the Company pursuant to Section 6 of Article I of the Company’s Bylaws that the Stockholder intends to nominate Mr. Johnny Guerry and Mr. Garold

Base for election to the Board of Directors of the Company at the 2013 Annual Meeting of Stockholders of the Company. Enclosed is the written consent of Mr. Guerry and Mr. Base to be named in the proxy statement of the Stockholder and to serve as directors of the Company if elected. The Stockholder represents (1) that the Stockholder is a beneficial owner of Common Stock entitled to vote at the 2013 Annual Meeting of Stockholders and intends to appear (or will direct a qualified representative of the Stockholder to appear) in person or by proxy at such meeting to nominate Mr. Guerry and Mr. Base; and (2) that the Stockholder intends to deliver a proxy statement and form of WHITE proxy to holders of at least the percentage of the Company’s outstanding capital stock required to elect the nominees.

Set forth below is certain information, including that required by Section 6 of Article I of the Company’s Bylaws. The information set forth below responds fully to all of the requirements of Section 6 of Article I of the Company’s Bylaws.

The Stockholder believes that Mr. Guerry and Mr. Base would be deemed “independent” under the NASDAQ Marketplace Rules. The Stockholder also believes that Mr. Base would qualify as an “audit committee financial expert,” as that term is defined by the Securities and Exchange Commission (SEC) and the NASDAQ Marketplace Rules.

Mr. Guerry’s financial background, combined with his extensive knowledge of the banking industry, qualify him to serve on the Company’s board of directors. Specifically, his extensive experience with, and understanding of, financial issues will allow him to provide the board with valuable recommendations and ideas. In addition, Mr. Guerry’s extensive knowledge of the banking industry makes him a valuable source of information, and will allow him to provide useful insight and advice.

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Mr. Base’s financial and accounting background, combined with his extensive knowledge of the banking industry and his experience as a Chief Executive Officer of financial institutions, qualify him to serve on the Company’s board of directors. Specifically, his extensive experience with, and understanding of, financial and accounting issues will allow him to provide the board with valuable recommendations and ideas.

Furthermore, the role of an effective director inherently requires certain personal qualities, such as integrity, as well as the ability to comprehend, discuss and critically analyze materials and issues that are presented so that the director may exercise judgment and reach conclusions in fulfilling his duties and fiduciary obligations. The Stockholder believes that the background and expertise of each of Mr. Guerry and Mr. Base, as set forth below, evidence those abilities and are appropriate to his serving on the Company’s board of directors.

Except as otherwise set forth herein, Mr. Guerry is not, nor has he been within the past year, a party to any contract, arrangement or understanding with any person with respect to any securities of the Company, including, but not limited to joint ventures, loan or option arrangements, puts or calls, guarantees against loss or guarantees of profit, division of losses or profits, or the giving or withholding of proxies.

Except as otherwise set forth herein, Mr. Guerry does not have, nor do any of his associates have, any arrangement or understanding with any person with respect to any future employment with the Company or its affiliates or with respect to any future transactions to which the Company or any of its affiliates will or may be a party.

Except as otherwise set forth herein, Mr. Base is not, nor has he been within the past year, a party to any contract, arrangement or understanding with any person with respect to any securities of the Company, including, but not limited to joint ventures, loan or option arrangements, puts or calls, guarantees against loss or guarantees of profit, division of losses or profits, or the giving or withholding of proxies.

Except as otherwise set forth herein, Mr. Base does not have, nor do any of his associates have, any arrangement or understanding with any person with respect to any future employment with the Company or its affiliates or with respect to any future transactions to which the Company or any of its affiliates will or may be a party.

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Directorships of Other Publicly Owned Companies

Neither Mr. Guerry nor Mr. Base is presently serving as a director of any corporation, partnership or other entity that has a class of equity securities registered under the Securities Exchange Act of 1934, as amended, or subject to the requirements of Section 15(d) of such Act, or any company registered as an investment company under the Investment Company Act of 1940.

Material Proceedings Adverse to the Company

To the knowledge of the Stockholder and the nominees, there are no material proceedings to which the nominees, or any of their associates, is a party adverse to the Company or any of its subsidiaries, and neither the nominees nor any of their associates has a material interest adverse to the Company or any of its subsidiaries.

Transactions In Stock of the Company

The transactions identified on Appendix A are the only transactions during the past two years with regard to the Common Stock made by the Stockholder or the nominees. Neither the Stockholder nor the nominees used margin account loans in connection with their transactions in Common Stock.

Arrangements or Understandings with Other Persons

Mr. Guerry has agreements with the Stockholder, whereby he is indemnified by the Stockholder for any liabilities he may incur in connection with his duties, including the intended solicitation of proxies for use at the 2013 Annual Meeting of Stockholders of the Company. The Stockholder will reimburse Mr. Guerry and Mr. Base for any expenses that they reasonably incur in connection with the intended solicitation of proxies for use at the 2013 Annual Meeting of Stockholders of the Company. To Mr. Guerry’s knowledge, he has no arrangement or understandings with any other person pursuant to which he was or is to be selected as a director or nominee for election as a director of the Company. To Mr. Base’s knowledge, he has no arrangement or understandings with any other person pursuant to which he was or is to be selected as a director or nominee for election as a director of the Company.

As of the date of this letter, the Stockholder has not formally retained any person to make solicitations or recommendations to stockholders for the purpose of assisting in the election of the nominees as directors.

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Absence of any Family Relationships

Mr. Guerry does not have any family relationship with any director or officer of the Company. Mr. Base does not have any family relationship with any director or officer of the Company.

Absence of Involvement in Certain Legal Proceedings

To the knowledge of Mr. Guerry, and based on information in his possession:

a. Since January 1, 2012, no petition under the federal bankruptcy laws or any state insolvency law has been filed by or against Mr. Guerry, and no receiver, fiscal agent or similar officer has been appointed by a court for the business or property of Mr. Guerry. In addition, since January 1, 2012, no petition under the federal bankruptcy laws or any state insolvency law has been filed by or against, and no receiver, fiscal agent or similar officer has been appointed by a court for the business or property of any partnership in which he is or was a general partner, or any corporation or business association of which he is or was an executive officer.

b. Mr. Guerry has not been convicted in a criminal proceeding nor has he been the named subject of any criminal proceeding which is presently pending (excluding traffic violations or similar misdemeanors).

c. Since January 1, 2012, Mr. Guerry has not been the subject of any court order, judgment or decree, not subsequently reversed, suspended or vacated, permanently or temporarily enjoining (or otherwise limiting) him from (A) acting as a futures commission merchant, introducing broker, commodity trading advisor, commodity pool operator, floor broker, leverage transaction merchant, any other person regulated by the Commodity Futures Trading Commission (“CFTC”) or any associated person of any of the foregoing, or as an investment advisor, underwriter, broker or dealer in securities, or as an affiliated person, director or employee of any investment company, bank, savings and loan association or insurance company, or engaging in or continuing any conduct or practice in connection with any such activity, (B) engaging in any type of business practice, or (C) engaging in any activity in connection with the purchase or sale of any security or commodity or in connection with any violation of federal or state securities laws or federal commodities laws.

d. Since January 1, 2012, Mr. Guerry has not been the subject of any order, judgment or decree not subsequently reversed, suspended or vacated, of any federal or state authority barring, suspending or otherwise limiting for more than 60 days his right to be engaged in any activity described in clause c. above, or his right to be associated with persons engaged in any such activity.

e. Since January 1, 2012, Mr. Guerry has not been found by a court of competent jurisdiction in a civil action or by the Securities and Exchange Commission (“SEC”) or the CFTC to have violated any federal or state securities law or any federal commodities law, where such judgment or finding has not been subsequently reversed, suspended or vacated.

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To the knowledge of Mr. Base, and based on information in his possession:

a. Since January 1, 2012, no petition under the federal bankruptcy laws or any state insolvency law has been filed by or against Mr. Base, and no receiver, fiscal agent or similar officer has been appointed by a court for the business or property of Mr. Base. In addition, since January 1, 2012, no petition under the federal bankruptcy laws or any state insolvency law has been filed by or against, and no receiver, fiscal agent or similar officer has been appointed by a court for the business or property of any partnership in which he is or was a general partner, or any corporation or business association of which he is or was an executive officer.

b. Mr. Base has not been convicted in a criminal proceeding nor has he been the named subject of any criminal proceeding which is presently pending (excluding traffic violations or similar misdemeanors).

c. Since January 1, 2012, Mr. Base has not been the subject of any court order, judgment or decree, not subsequently reversed, suspended or vacated, permanently or temporarily enjoining (or otherwise limiting) him from (A) acting as a futures commission merchant, introducing broker, commodity trading advisor, commodity pool operator, floor broker, leverage transaction merchant, any other person regulated by the CFTC or any associated person of any of the foregoing, or as an investment advisor, underwriter, broker or dealer in securities, or as an affiliated person, director or employee of any investment company, bank, savings and loan association or insurance company, or engaging in or continuing any conduct or practice in connection with any such activity, (B) engaging in any type of business practice, or (C) engaging in any activity in connection with the purchase or sale of any security or commodity or in connection with any violation of federal or state securities laws or federal commodities laws.

d. Since January 1, 2012, Mr. Base has not been the subject of any order, judgment or decree not subsequently reversed, suspended or vacated, of any federal or state authority barring, suspending or otherwise limiting for more than 60 days his right to be engaged in any activity described in clause c. above, or his right to be associated with persons engaged in any such activity.

e. Since January 1, 2012, Mr. Base has not been found by a court of competent jurisdiction in a civil action or by the Securities and Exchange Commission (“SEC”) or the CFTC to have violated any federal or state securities law or any federal commodities law, where such judgment or finding has not been subsequently reversed, suspended or vacated.

Absence of Certain Transactions

To the best knowledge of Mr. Guerry, and based on information in his possession, since the beginning of the Company’s last fiscal year, neither Mr. Guerry nor any member of his

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immediate family has had any direct or indirect material interest in any transaction in which the Company was or is a participant, and neither Mr. Guerry nor any member of his immediate family has any direct or indirect material interest in any currently proposed transaction in which the Company is to be a participant.

To the best knowledge of Mr. Base, and based on information in his possession, since the beginning of the Company’s last fiscal year, neither Mr. Base nor any member of his immediate family has had any direct or indirect material interest in any transaction in which the Company was or is a participant, and neither Mr. Base nor any member of his immediate family has any direct or indirect material interest in any currently proposed transaction in which the Company is to be a participant.

Section 16 Compliance

Mr. Guerry is not required to file reports under Section 16 of the Securities Exchange Act of 1934, as amended, with respect to the Common Stock of the Company.

Mr. Base is not required to file reports under Section 16 of the Securities Exchange Act of 1934, as amended, with respect to the Common Stock of the Company.

MHC Mutual Conversion Fund, L.P.

c/o Clover Partners, L.P.

100 Crescent Court

Suite 575

Dallas, Texas 75201

The Stockholder is engaged in various interests, including investments.

Other than the parties named herein, no other stockholder is known to the Stockholder to be supporting the Stockholder’s nominees.

The Stockholder is the beneficial owner of 377,732 shares of Common Stock, and the details of the Stockholder’s beneficial ownership of Common Stock are found on Appendix B.

* * *

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If the Company’s board of directors or a committee thereof believes this notice is incomplete or otherwise deficient in any respect, please contact the Stockholder immediately so that the Stockholder may promptly address any alleged deficiencies.

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Appendix A

Transactions by MHC Mutual Conversion Fund, L.P. (all of the transactions were acquisitions):

Transactions by Johnny Guerry other than indirectly by MHC Mutual Conversion Fund, L.P.: None.

Transactions by Garold R. Base (all of the transactions were acquisitions):

Appendix B

CONSENT OF PROPOSED NOMINEE

I, Johnny Guerry, hereby consent to be named in the proxy statement of the MHC Mutual Conversion Fund, L.P. to be used in connection with its solicitation of proxies from the Stockholders of Hampden Bancorp, Inc. for use in voting at the 2013 Annual Meeting of Stockholders of Hampden Bancorp, Inc. and I hereby consent and agree to serve a director of Hampden Bancorp, Inc. if elected at such Annual Meeting.

Dated: May 1, 2013

CONSENT OF PROPOSED NOMINEE

I, Garold R. Base, hereby consent to be named in the proxy statement of the MHC Mutual Conversion Fund, L.P. to be used in connection with its solicitation of proxies from the Stockholders of Hampden Bancorp, Inc. for use in voting at the 2013 Annual Meeting of Stockholders of Hampden Bancorp, Inc. and I hereby consent and agree to serve a director of Hampden Bancorp, Inc. if elected at such Annual Meeting.

Dated: May 1, 2013

Exhibit A

MORGAN STANLEY

PRIME BROKERAGE

1221 Avenue of the Americas, 4th Floor

New York, NY 10020

(212) 762-5193

4/24/2013

Secretary of the Corporation

Hampden Bancorp, Inc.

19 Harrison Avenue

Springfield, Massachusetts 01102

To Whom It May Concern:

At the request of Clover Partners LP, we are sending you this letter to verify that MHC Mutual Conversion Fund LP has continuously held shares in the common stock of Hampden Bancorp (ISIN: US40867E1073) since 5/11/2011 and currently holds 377,732 shares of this security, as of 4/23/2013, at Morgan Stanley & Co. LLC.

Regards,

While this information is based on or from sources Morgan Stanley (“MS”) believes to be reliable, no representation is made that the information is accurate, complete, or current and MS disclaims any and all liability relating to these materials, including, without limitation, any express or implied representation or warranties for statements or errors contained in, or omissions from, these materials. The information provided is not an offer or solicitation by MS of the purchase or sale or any security or commodity. The information provided is for private use only and is given in the strictest confidence on the express understanding that it is without any guarantee or responsibility on the part of Morgan Stanley, its parents, affiliates, their respective officers, directors and employees, and any and all of its and their successors and assigns.

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