WMPN William Penn Bancorporation

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the Securities

Exchange Act of 1934

(Amendment No. __)

Check the appropriate box:

William Penn Bancorporation

(Exact Name of Registrant as Specified in its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

Joint Proxy Statement/Prospectus

MERGER PROPOSED—YOUR VOTE IS VERY IMPORTANT

Dear Shareholder:

On October 31, 2024, Mid Penn Bancorp, Inc., or Mid Penn, and William Penn Bancorporation, or William Penn, entered into a merger agreement, under which William Penn will merge with and into Mid Penn, with Mid Penn remaining as the surviving entity. Mid Penn and William Penn are each holding a special meeting for their respective shareholders to vote on the proposals necessary to complete the merger.

Mid Penn shareholders will vote to approve the issuance of shares of Mid Penn common stock in connection with the merger and on other matters described below at the special meeting of shareholders to be held virtually at 9:00 AM, Eastern Time, on April 2, 2025. William Penn shareholders will vote to adopt the merger agreement and on the other matters described below at a special meeting of shareholders to be held at William Penn’s corporate office located at 10 Canal Street, Suite 104, Bristol, Pennsylvania 19007 at 9:00 AM, Eastern Time, on April 2, 2025. Information regarding how Mid Penn shareholders and William Penn shareholders can attend and participate in their respective special meetings of shareholders is included in the proxy card for the respective companies included with this joint proxy statement/prospectus.

If the merger is completed, William Penn shareholders will have the right to receive for each share of William Penn common stock they own 0.426 shares of Mid Penn common stock. Cash will be paid in lieu of any fractional shares. The maximum number of shares of Mid Penn common stock estimated to be issuable upon completion of the merger is 3,922,700. Following the completion of the merger, former William Penn shareholders will hold approximately 16.85% of Mid Penn’s common stock.

The common stock of Mid Penn trades on the Nasdaq Global Market under the symbol “MPB” and the common stock of William Penn trades on the Nasdaq Capital Market under the symbol “WMPN.” On October 31, 2024, which was the last trading date preceding the public announcement of the proposed merger, the closing price of Mid Penn common stock and William Penn common stock was $31.59 per share and $12.74 per share, respectively. On February 6, 2025, the most recent practicable trading day prior to the printing of this joint proxy statement/prospectus, the closing price of Mid Penn common stock and William Penn common stock was $30.28 per share and $12.58 per share, respectively. The market price of both Mid Penn common stock and William Penn common stock will fluctuate before the completion of the merger; therefore, you are urged to obtain current market quotations for Mid Penn common stock and William Penn common stock. Additionally, as described in more detail elsewhere in this joint proxy statement/prospectus, under the terms of the merger agreement, if the average price of Mid Penn common stock over a specified period of time decreases below certain specified thresholds, William Penn would have a right to terminate the merger agreement, unless Mid Penn elects to increase the exchange ratio, which would result in additional shares of Mid Penn common stock being issued.

The Mid Penn board of directors has determined that the merger is advisable and in the best interests of Mid Penn and its shareholders, and the Mid Penn board of directors unanimously recommends that the Mid Penn shareholders vote “FOR” the approval of the issuance by Mid Penn of shares of Mid Penn common stock to be issued to holders of William Penn common stock as merger consideration in connection with the merger.

The William Penn board of directors has determined that the merger is advisable and in the best interests of William Penn and its shareholders, and the William Penn board of directors unanimously recommends that the William Penn shareholders vote “FOR” the approval and adoption of the merger agreement.

Your vote is very important. Whether or not you plan to attend your shareholders’ meeting, please take the time to vote by completing and mailing the enclosed proxy card in accordance with the instructions on the proxy card. Mid Penn and William Penn shareholders may also cast their votes over the Internet or by telephone in accordance with the instructions on the Mid Penn or William Penn proxy card or voting instructions, as the case may be. We cannot complete the merger unless, among other matters, (i) William Penn shareholders approve and adopt the merger agreement and (ii) Mid Penn shareholders approve the issuance of shares of Mid Penn common stock in connection with the merger.

You should read this entire joint proxy statement/prospectus, including the annexes hereto and the documents incorporated by reference herein, carefully because it contains important information about the merger and the related transactions. In particular, you should read carefully the information under the section entitled “Risk Factors” beginning on page 39. You can also obtain information about Mid Penn and William Penn from documents that each has filed with the Securities and Exchange Commission.

We strongly support this combination of our companies and join with the other members of our boards of directors in enthusiastically recommending that you vote in favor of the merger.

Rory G. Ritrievi		Kenneth J. Stephon
President and Chief Executive Officer		Chairman, President and Chief Executive Officer
Mid Penn Bancorp, Inc.		William Penn Bancorporation

The shares of Mid Penn common stock to be issued to William Penn shareholders in the merger are not deposits or savings accounts or other obligations of any bank or savings association, and are not insured by the Federal Deposit Insurance Corporation or any other governmental agency.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved the Mid Penn common stock to be issued in the merger, or passed upon the adequacy or accuracy of this joint proxy statement/prospectus. Any representation to the contrary is a criminal offense.

The date of this joint proxy statement/prospectus is February 7, 2025, and it is first being mailed or otherwise delivered to Mid Penn shareholders and William Penn shareholders on or about February 14, 2025.

This document incorporates important business and financial information about Mid Penn and William Penn that is not included in or delivered with this document. This information is available without charge to shareholders upon written or oral request at either Mid Penn’s or William Penn’s address and telephone number listed on page i. To obtain timely delivery, Mid Penn shareholders must request the information no later than March 26, 2025 and William Penn shareholders must request this information no later than March 26, 2025. Please see “Where You Can Find More Information” on page 129 for instructions to request this and certain other information regarding Mid Penn and William Penn.

MID PENN BANCORP, INC.

2407 PARK DRIVE

HARRISBURG, PENNSYLVANIA 17110

NOTICE OF SPECIAL MEETING OF SHAREHOLDERS

TO BE HELD ON APRIL 2, 2025

TO THE SHAREHOLDERS OF MID PENN BANCORP, INC.:

NOTICE IS HEREBY GIVEN that a special meeting of shareholders of Mid Penn Bancorp, Inc., or Mid Penn, will be held virtually at 9:00 AM, Eastern Time, on April 2, 2025, to consider and vote on:

These items are described in more detail in the accompanying joint proxy statement/prospectus and its annexes. You should read these documents in their entirety before voting. We have fixed January 31, 2025 as the record date for determining those Mid Penn shareholders entitled to vote at the special meeting. Accordingly, only shareholders of record at the close of business on that date are entitled to notice of and to vote at the special meeting or any adjournment or postponement of the meeting.

Your board of directors has unanimously determined that the proposed merger is advisable and in the best interests of Mid Penn and its shareholders and unanimously recommends that you vote “FOR” the Mid Penn share issuance proposal and “FOR” the Mid Penn adjournment proposal. In accordance with the terms of the merger agreement, each director and executive officer of Mid Penn has agreed to vote all shares of Mid Penn common stock owned by him or her, and that he or she has the sole power to vote or direct the voting thereof, in favor of the Mid Penn share issuance proposal.

Your vote is very important, regardless of the number of shares of Mid Penn common stock that you own. We cannot complete the merger unless the issuance of shares of Mid Penn common stock in connection with the merger is approved by a majority of the votes cast at the Mid Penn special meeting.

Even if you plan to attend the special meeting (information regarding how you can attend and participate in the special meeting is included in the proxy card), Mid Penn requests that you complete, sign, date and return, as promptly as possible, the enclosed proxy card in the accompanying prepaid reply envelope or submit your proxy by telephone or Internet prior to the special meeting to ensure that your shares of Mid Penn common stock will be represented at the special meeting. If you hold your shares in “street name” through a bank, brokerage firm or other nominee, you should follow the procedures provided by your bank, brokerage firm or other nominee to vote your shares. If you fail to submit a proxy or to virtually attend the special meeting and vote or do not provide your bank, brokerage firm or other nominee with instructions as to how to vote your shares, as applicable, your shares of Mid Penn common stock will not be counted.

We urge you to vote as soon as possible so that your shares will be represented.

BY ORDER OF THE BOARD OF DIRECTORS,

Elizabeth O. Martin

Corporate Secretary

Harrisburg, Pennsylvania

February 7, 2025

WILLIAM PENN BANCORPORATION

10 CANAL STREET, SUITE 104

BRISTOL, PENNSYLVANIA 19007

NOTICE OF SPECIAL MEETING OF SHAREHOLDERS

TO BE HELD ON APRIL 2, 2025

TO THE SHAREHOLDERS OF WILLIAM PENN BANCORPORATION

NOTICE IS HEREBY GIVEN that a special meeting of shareholders of William Penn Bancorporation, or William Penn, will be held at William Penn’s corporate office located at 10 Canal Street, Suite 104, Bristol, Pennsylvania 19007 at 9:00 AM, Eastern Time, on April 2, 2025, to consider and vote on:

We have fixed January 31, 2025 as the record date for determining those William Penn shareholders entitled to vote at the special meeting. Accordingly, only shareholders of record at the close of business on that date are entitled to notice of and to vote at the special meeting or any adjournment or postponement of the meeting.

Your board of directors has unanimously determined that the proposed merger is advisable and in the best interests of William Penn and its shareholders and unanimously recommends that you vote “FOR” the William Penn merger proposal and “FOR” the William Penn adjournment proposal. In accordance with the terms of the merger agreement, each director and executive officer of William Penn has agreed to vote all shares of William Penn common stock owned by him or her, and that he or she has the sole power to vote or direct the voting thereof, in favor of approval and adoption of the merger agreement and the transactions contemplated thereby.

We urge you to vote as soon as possible so that your shares will be represented.

Your vote is very important, regardless of the number of shares of William Penn common stock that you own. We cannot complete the merger unless the affirmative vote of at least a majority of the votes entitled to vote on such proposal at the William Penn special meeting is voted to approve and adopt the William Penn merger proposal.

Even if you plan to attend the special meeting (information regarding how you can attend and participate in the special meeting is included in the proxy card), William Penn requests that you complete, sign, date and return, as promptly as possible, the enclosed proxy card in the accompanying prepaid reply envelope or submit your proxy by telephone or the Internet prior to the special meeting to ensure that your shares of William Penn common stock will be represented at the special meeting. If you hold your shares in “street name” through a bank, brokerage firm or other nominee, you should follow the procedures provided by your bank, brokerage firm or other nominee to vote your shares. If you fail to submit a proxy or attend the special meeting and vote or do not provide your bank, brokerage firm or other nominee with instructions as to how to vote your shares, your shares of William Penn common stock will not be counted and will have the same effect as a vote “AGAINST” the approval and adoption of the merger agreement.

BY ORDER OF THE BOARD OF DIRECTORS,

Jonathan T. Logan

Corporate Secretary

Bristol, Pennsylvania

February 7, 2025

WILLIAM PENN SHAREHOLDERS SHOULD NOT SEND STOCK CERTIFICATES AT THIS TIME. YOU WILL BE SENT SEPARATE INSTRUCTIONS ABOUT HOW TO RECEIVE THE MERGER CONSIDERATION AND THE SURRENDER OF YOUR STOCK CERTIFICATES.

HOW TO OBTAIN ADDITIONAL INFORMATION

This joint proxy statement/prospectus incorporates by reference important business and financial information about Mid Penn and William Penn that is not included in or delivered with this document. You can obtain free copies of this information through the SEC website at https://www.sec.gov. You will also be able to obtain these documents, free of charge, from Mid Penn at www.midpennbank.com, under the heading “SEC Filings” or from William Penn by accessing William Penn’s website at www.williampenn.bank, under the heading “Investor Relations.” You can also obtain free copies of this information by writing or calling:

You will not be charged for any of these documents that you request. In order to obtain timely delivery of the documents, you must request the information no later than five business days before the date of the applicable special meeting. Therefore, you must request the information no later than March 26, 2025, with respect to Mid Penn information, and no later than March 26, 2025 with respect to William Penn information.

If you are a shareholder of William Penn and have questions about the merger or the special meeting of William Penn, would like additional copies of this document or proxy cards, or need any other information related to the proxy solicitations, you may also contact Alliance Advisors at (833) 215-7310.

For a more detailed description of the information incorporated by reference in this joint proxy statement/prospectus and how you may obtain it, see the section entitled “Where You Can Find More Information” on page 129 and “Incorporation of Certain Documents by Reference” on page 130.

All information concerning Mid Penn and its subsidiaries has been furnished by Mid Penn, and all information concerning William Penn and its subsidiaries has been furnished by William Penn.

You should rely only on the information contained or incorporated by reference in this joint proxy statement/prospectus when evaluating the merger agreement and the proposed merger. We have not authorized anyone to provide you with information that is different from what is contained in this joint proxy statement/prospectus. This joint proxy statement/prospectus is dated February 7, 2025. You should not assume that the information contained in this joint proxy statement/prospectus is accurate as of any date other than such date. Further, you should not assume that the information incorporated by reference into this joint proxy statement/prospectus is accurate as of any date other than the date of the incorporated document. Neither the mailing of this joint proxy statement/prospectus nor the issuance of shares of Mid Penn common stock as contemplated by the merger agreement shall create any implication to the contrary.

This joint proxy statement/prospectus does not constitute an offer to sell, or a solicitation of an offer to buy, any securities or the solicitation of a proxy, in any jurisdiction in which or from any person to whom it is not lawful to make any such offer or solicitation in such jurisdiction.

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ABOUT THIS JOINT PROXY STATEMENT/PROSPECTUS

This document, which forms part of a registration statement on Form S-4 filed with the SEC by Mid Penn (File No. 333-284342), constitutes a prospectus of Mid Penn under the Securities Act of 1933, as amended, which we refer to as the “Securities Act,” with respect to the shares of common stock, par value $1.00 per share, of Mid Penn, which we refer to as “Mid Penn common stock,” to be issued pursuant to the Agreement and Plan of Merger, dated as of October 31, 2024, by and between Mid Penn and William Penn, which we refer to as the “merger agreement.” This document also constitutes a proxy statement of Mid Penn and William Penn under the Securities Exchange Act of 1934, which we refer to as the “Exchange Act.” It also constitutes a notice of meeting with respect to the special meetings, at which each of Mid Penn and William Penn shareholders will be asked to vote on proposals necessary to complete the merger. Mid Penn has supplied all information contained or incorporated by reference into this joint proxy statement/prospectus relating to Mid Penn, and William Penn has supplied all information contained or incorporated by reference into this joint proxy statement/prospectus relating to William Penn.

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TABLE OF CONTENTS

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QUESTIONS AND ANSWERS ABOUT THE MERGER AND THE SPECIAL MEETINGS

The following questions and answers briefly address some commonly asked questions about the merger (as defined below) and the shareholder meetings. They may not include all the information that is important to the shareholders of Mid Penn and William Penn. Shareholders of Mid Penn and William Penn should each read carefully this entire joint proxy statement/prospectus, including the annexes and other documents referred to in this joint proxy statement/prospectus.

Questions about the Merger

Mid Penn is providing this joint proxy statement/prospectus to its shareholders because the Mid Penn Board of Directors is soliciting their proxy for use at the Mid Penn special meeting of shareholders at which the Mid Penn shareholders will consider and vote on (i) the approval of the issuance by Mid Penn of shares of Mid Penn common stock to holders of common stock of William Penn as merger consideration (the “Mid Penn share issuance proposal”), and (ii) the approval of the authorization of the Mid Penn board of directors to adjourn the Mid Penn special meeting, if necessary, to solicit additional proxies, in the event there are not sufficient votes at the time of the special meeting to approve the Mid Penn share issuance proposal (the “Mid Penn adjournment proposal”). See “The Mid Penn Special Meeting,” beginning on page 111 for more information.

William Penn is providing this joint proxy statement/prospectus to its shareholders because the William Penn Board of Directors is soliciting their proxy for use at the William Penn special meeting of shareholders at which the William Penn shareholders will consider and vote on (i) the approval and adoption of the merger agreement which provides for, among other things, the merger of William Penn with and into Mid Penn (the “William Penn merger proposal”), and (ii) the approval of the authorization of the William Penn board of directors to adjourn the William Penn special meeting, if necessary, to solicit additional proxies, in the event there are not sufficient votes at the time of the special meeting to approve the William Penn merger proposal (the “William Penn adjournment proposal”). See “The William Penn Special Meeting,” beginning on page 115 for more information.

Information about these meetings, the merger and the other business to be considered at the meetings is contained in this joint proxy statement/prospectus. The merger cannot be completed unless the shareholders

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of Mid Penn approve the issuance by Mid Penn of shares of Mid Penn common stock to holders of common stock of William Penn as merger consideration, and the shareholders of William Penn approve and adopt the merger agreement.

On October 31, 2024, which was the last trading date preceding the public announcement of the proposed merger, the closing price of Mid Penn common stock was $31.59 per share, which, after giving effect to the 0.426 exchange ratio, would result in merger consideration with an implied value of approximately $13.46 per share of William Penn common stock. On February 6, 2025, the most recent practicable trading day prior to the printing of this joint proxy statement/prospectus, the closing price of Mid Penn common stock was $30.28 per share, which, after giving effect to the 0.426 exchange ratio, would result in merger consideration with an implied value of approximately $12.90 per share of William Penn common stock. The market price of both Mid Penn common stock and William Penn common stock will fluctuate before the completion of the merger; therefore, you are urged to obtain current market quotations for Mid Penn common stock and William Penn common stock.

Because of the number of shares of Mid Penn common stock being issued in the merger, the percentage ownership interest in Mid Penn represented by the existing shares of Mid Penn common stock will be diluted. Mid Penn shareholders will not receive any merger consideration and will continue to own their existing shares of Mid Penn common stock after the merger.

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Stock Options: At the effective time of the merger, each option to purchase shares of William Penn common stock which is outstanding and unexercised immediately prior to the effective time of the merger, whether or not then vested and exercisable, shall cease to represent a right to acquire shares of William Penn common stock and will be converted into an option to acquire, on the same terms and conditions as were applicable under such William Penn stock option (including vesting and exercisability terms) immediately prior to the effective time of the merger, the number of shares of Mid Penn common stock equal to (a) the number of shares of William Penn common stock subject to such stock option multiplied by (b) 0.426. Such product will be rounded down to the nearest whole share. The exercise price per share (rounded up to the nearest whole cent) of each Mid Penn stock option issued for the William Penn stock option will be equal to (y) the exercise price per share of shares of William Penn common stock that were purchasable pursuant to such William Penn stock option divided by (z) 0.426. If an officer, director, or employee of William Penn has received a stock option award and they are terminated within two years of the completion of the merger, any unvested stock option awards will automatically vest upon termination.

Restricted Stock Awards: At the effective time of the merger, each restricted stock award of William Penn common stock which is outstanding immediately prior to the effective time of the merger and with respect to which the applicable restrictions have not yet lapsed, shall cease to represent a right to acquire shares of William Penn common stock and will be converted into the right to receive, on the same terms and conditions as were applicable under such William Penn restricted stock award (including vesting terms)

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immediately prior to the effective time of the merger, the number of shares of Mid Penn common stock equal to (a) the number of shares of William Penn common stock subject to such restricted stock award multiplied by (b) 0.426. Such product will be rounded down to the nearest whole share. If an officer, director, or employee of William Penn has received a restricted stock award and they are terminated within two years of the completion of the merger, any unvested restricted stock awards will automatically vest upon termination.

This tax treatment may not apply to all William Penn shareholders. Determining the actual tax consequences of the merger to William Penn shareholders can be complicated. William Penn shareholders should consult their own tax advisor for a full understanding of the merger’s tax consequences that are particular to each shareholder. For further discussion of the material U.S. federal income tax consequences of the merger, see “Material United States Federal Income Tax Consequences of the Merger,” beginning on page 108.

Questions about the Mid Penn Special Meeting

As of the record date, directors and executive officers of Mid Penn and their affiliates had the right to vote 1,532,691 shares of Mid Penn common stock, or 7.9% of the outstanding Mid Penn common stock entitled to be voted at the special meeting. Each of the directors and executive officers of Mid Penn has entered into a separate voting agreement with William Penn and has agreed to vote all shares of Mid Penn common stock owned by him or her that he or she has the sole power to vote or direct the voting thereof in favor of adoption of the share issuance proposal.

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Voting by Proxy. Mid Penn shareholders of record may vote their Mid Penn shares by completing and returning the enclosed proxy card. Your proxy will be voted in accordance with your instructions. If you submit a properly executed and dated proxy, but do not specify a choice on one of the proposals described in this joint proxy statement/prospectus, your proxy will be voted in favor of that proposal.

Voting by Internet. If you are a registered shareholder, you may vote electronically through the Internet by following the instructions included on your proxy card. If your shares are registered in the name of a broker or other nominee, you may be able to vote via the Internet. If so, the voting form your nominee sends you will provide Internet instructions.

Voting by Phone. Use any touch-tone telephone to transmit your voting instructions up until 11:59 p.m. Eastern Time the day before the cut-off date or meeting date. Have your proxy card in hand when you call 1-866-883-0222 and then follow the instructions.

Voting Virtually at the Special Meeting. Mid Penn shareholders of record may virtually attend the Mid Penn special meeting and vote. Information regarding how to virtually attend the special meeting is included in the proxy card. If your shares are registered in the name of a broker or other nominee and you wish to vote at the meeting you will need to obtain a legal proxy from your bank or brokerage firm. Please consult the voting form sent to you by your bank or broker to determine how to obtain a legal proxy in order to vote at the special meeting.

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Any shareholder entitled to vote virtually at the special meeting may vote regardless of whether a proxy has been previously given, and such vote will revoke any previous proxy, but the mere virtual presence (without notifying Mid Penn’s Corporate Secretary) of a shareholder at the special meeting will not constitute revocation of a previously given proxy. A shareholder may change his or her vote up and until the time that votes are counted but not thereafter.

Mid Penn Bancorp, Inc.

2407 Park Drive

Harrisburg, Pennsylvania 17110

Attention: Investor Relations

Telephone: (866) 642-7736

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Questions about the William Penn Special Meeting

As of the record date, directors and executive officers of William Penn and their affiliates had the right to vote 785,058 shares of William Penn common stock, or approximately 8.5% of the outstanding William Penn common stock entitled to be voted at the William Penn special meeting. Each of the directors and executive officers of William Penn has entered into a separate voting agreement with Mid Penn to vote all shares of William Penn common stock owned by him or her, and that he or she has the sole power to vote or direct the voting thereof, in favor of the adoption of the merger agreement.

Voting by Proxy. You may vote your William Penn shares by completing and returning the enclosed proxy card. Your proxy will be voted in accordance with your instructions. If you submit a properly executed and dated proxy, but do not specify a choice on one of the proposals described in this joint proxy statement/prospectus, your proxy will be voted in favor of that proposal.

Voting by Internet. If you are a registered shareholder, you may vote electronically through the Internet by following the instructions included on your proxy card. If your shares are registered in the name of a broker or other nominee, you may be able to vote via the Internet. If so, the voting form your nominee sends you will provide Internet instructions.

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Voting by Phone. Use any touch-tone telephone to transmit your voting instructions up until 11:59 p.m. Eastern Time the day before the cut-off date or meeting date. Have your proxy card in hand when you call 1-800-690-6903 and then follow the instructions.

Voting at the Special Meeting. You may attend the William Penn special meeting and vote. Information regarding how to attend the special meeting is included in the proxy card. If your shares are registered in the name of a broker or other nominee and you wish to vote at the meeting, you will need to obtain a legal proxy from your bank or brokerage firm. Please consult the voting form sent to you by your bank or broker to determine how to obtain a legal proxy in order to vote at the William Penn special meeting.

The William Penn Bank 401(k) Retirement Savings Plan (the “401(k) Plan”): William Penn shares held by the 401(k) plan are voted by the trustee, but each participant (or beneficiary of a deceased participant) is entitled to direct the trustee how to vote the shares of William Penn common stock that are allocated to his or her account under the 401(k) Plan. All shares of William Penn stock allocated to accounts for which the plan trustee did not receive instructions from a participant will be voted by the plan trustee in the same proportion as the shares for which it has received instructions, subject to the trustee’s discretion and in accordance with applicable fiduciary duties under the Employee Retirement Income Security Act of 1974, as amended. The deadline for returning your voting instruction form to the trustee of the 401(k) Plan is March 28, 2025.

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Holders of record of William Penn common stock can vote at the special meeting. If you are not a shareholder of record, you must obtain a proxy, executed in your favor, from the record holder of your shares, such as a broker, bank or other nominee, to be able to vote at the special meeting. If you plan to attend the special meeting, you must hold your shares in your own name or have a letter from the record holder of your shares confirming your ownership.

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Any shareholder entitled to vote at the special meeting may vote regardless of whether a proxy has been previously given, and such vote will revoke any previous proxy, but the mere presence (without notifying William Penn’s Corporate Secretary) of a shareholder at the special meeting will not constitute revocation of a previously given proxy. A shareholder may change his or her vote up and until the time that votes are counted but not thereafter.

William Penn will bear the cost of preparing and assembling these proxy materials for the William Penn special meeting. The cost of printing and mailing these proxy materials will be shared equally between Mid Penn and William Penn. The solicitation of proxies or votes for the William Penn special meeting may also be made in person, by telephone, or by electronic communication by William Penn’s directors, officers, and employees, none of whom will receive any additional compensation for such solicitation activities. In addition, William Penn may reimburse brokerage firms and other persons representing beneficial owners of shares for their expenses in forwarding solicitation material to such beneficial owners.

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William Penn Bancorporation

10 Canal Street, Suite 104

Bristol, Pennsylvania 19007

Attention: Jonathan T. Logan

Telephone: (267) 540-8500

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SUMMARY

This summary highlights information contained elsewhere in this joint proxy statement/prospectus and may not contain all of the information that is important to you. We urge you to carefully read the entire joint proxy statement/prospectus and the other documents to which we refer in order to fully understand the merger and the related transactions. See “Where You Can Find More Information.”

Information about the Parties

Mid Penn Bancorp, Inc.

Mid Penn Bancorp, Inc. is the financial holding company for Mid Penn Bank, a full-service Pennsylvania chartered bank and trust company originally organized in 1868, as well an insurance agency subsidiary formed to further expand Mid Penn’s suite of products and services. Mid Penn is regulated by the Board of Governors of the Federal Reserve System. Mid Penn Bank is regulated by the Pennsylvania Department of Banking and Securities and the Federal Deposit Insurance Corporation.

Headquartered in Millersburg, Pennsylvania, Mid Penn Bank services its customers and communities through forty-five retail banking locations located in the Pennsylvania counties of Berks, Blair, Bucks, Center, Chester, Clearfield, Cumberland, Dauphin, Fayette, Huntingdon, Lancaster, Lehigh, Luzerne, Montgomery, Perry, Schuylkill and Westmoreland, along with three retail banking locations located in the New Jersey counties of Middlesex and Monmouth. Mid Penn Bank engages in full-service commercial banking and trust business, making available to the community a wide range of financial services, including, but not limited to, mortgage and home equity loans, secured and unsecured commercial and consumer loans, lines of credit, construction financing, farm loans, community development loans, loans to non-profit entities and local government loans, and various types of deposits and IRAs. In addition, the Bank provides a full range of trust and wealth management services through its Trust Department. Deposits are insured by the Federal Deposit Insurance Corporation to the extent provided by law. The financial services are provided to individuals, partnerships, non-profit organizations, and corporations through its retail banking offices located throughout Pennsylvania and two counties in New Jersey.

Mid Penn also fulfills the insurance needs of both existing and potential customers through a wholly owned subsidiary, MPB Risk Services, LLC, doing business as MPB Insurance and Risk Management. In 2021, Mid Penn established MPB Launchpad Fund I, LLC to hold certain financial holding company eligible investments.

Our principal business is to supervise and coordinate the business of the Bank and our nonbank subsidiaries, and to provide those subsidiaries with the capital and resources necessary to fulfill their respective missions.

The principal executive offices of Mid Penn are located at 2407 Park Drive, Harrisburg, Pennsylvania 17110 and its telephone number is (866) 642-7736.

Mid Penn common stock is traded on The Nasdaq Global Market under the symbol “MPB.”

William Penn Bancorporation

William Penn was incorporated in 2020 as a bank holding company, organized under the laws of Maryland, as the successor to William Penn Bancorp, Inc. upon completion of William Penn Bank’s “second-step” conversion from the mutual holding company structure to the stock holding company structure. The second-step conversion was completed on March 24, 2021. William Penn is the bank holding company for William Penn Bank, a full-service Pennsylvania chartered stock savings bank. William Penn is regulated by the Board of Governors of the Federal Reserve System and William Penn Bank is regulated by the Pennsylvania Department of Banking and Securities and the Federal Deposit Insurance Corporation.

William Penn Bank offers consumer and commercial banking services to individuals, businesses, and nonprofit organizations throughout the Delaware Valley area through twelve full-service branch offices in Bucks and

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Philadelphia Counties in Pennsylvania, and Burlington, Camden and Mercer Counties in New Jersey. William Penn Bank’s principal business consists of originating one- to four- family residential real estate mortgage loans, home equity lines of credit, residential construction loans, one- to four-family investor commercial real estate loans, non-residential real estate loans, multi-family loans and construction land loans.

William Penn Bank’s wholly-owned subsidiary, WPSLA Investment Corporation, also holds certain investment securities for William Penn Bank.

The principal executive offices of William Penn are located at 10 Canal Street, Suite 104, Bristol, Pennsylvania 19007, and its telephone number is (267) 540-8500.

William Penn common stock is traded on The Nasdaq Capital Market under the symbol “WMPN.”

The Merger and the Merger Agreement (pages 49 and 92)

The terms and conditions of the merger are contained in the merger agreement, which is attached as Annex A to this joint proxy statement/prospectus and incorporated by reference herein. Please carefully read the merger agreement as it is the legal document that governs the merger.

Pursuant to the merger agreement, William Penn will merge with and into Mid Penn with Mid Penn as the surviving corporation. Immediately after the merger, William Penn Bank will merge with and into Mid Penn Bank, with Mid Penn Bank as the surviving bank.

Mid Penn Will Hold Its Special Meeting on April 2, 2025 (page 111)

The Mid Penn special meeting will be held virtually on April 2, 2025 at 9:00 AM, Eastern Time. At the special meeting, Mid Penn shareholders will be asked to:

Record Date. Only holders of record of Mid Penn common stock at the close of business on January 31, 2025 will be entitled to vote at the special meeting. Each share of Mid Penn common stock is entitled to one vote. As of the Mid Penn record date, there were 19,355,797 shares of Mid Penn common stock issued and outstanding and entitled to vote at the special meeting.

Required Vote. The affirmative vote, in person or by proxy, of a majority of votes cast at the special meeting is required to approve the Mid Penn share issuance proposal and the Mid Penn adjournment proposal. The presence, in person or by proxy, of a majority of the votes which all shareholders are entitled to cast is necessary to constitute a quorum in order to transact business at the special meeting.

As of the record date, directors and executive officers of Mid Penn and their affiliates had the right to vote 1,532,691 shares of Mid Penn common stock, or 7.9% of the outstanding Mid Penn common stock entitled to be voted at the special meeting. Each of the directors and executive officers of Mid Penn has entered into a separate voting agreement with William Penn, pursuant to which each such director and executive officer has agreed to vote all shares of Mid Penn common stock over which he or she has the sole power to vote or direct the voting thereof in favor of the Mid Penn share issuance proposal and certain related matters and against alternative transactions.

William Penn Will Hold Its Special Meeting on April 2, 2025 (page 115)

The William Penn special meeting will be held at William Penn’s corporate office located at 10 Canal Street, Suite 104, Bristol, Pennsylvania 19007 on April 2, 2025 at 9:00 AM, Eastern Time. At the special meeting, William Penn shareholders will be asked to:

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Record Date. Only holders of record of William Penn common stock at the close of business on January 31, 2025 will be entitled to vote at the special meeting. Each share of William Penn common stock is entitled to one vote. As of the William Penn record date, there were 9,208,217 shares of William Penn common stock issued and outstanding and entitled to vote at the special meeting.

Required Vote. Approval of the William Penn merger proposal requires the affirmative vote of a majority of the total number of shares outstanding and entitled to vote at the special meeting, in person or by proxy. Approval of the William Penn adjournment proposal requires the affirmative vote of a majority of the votes cast at the special meeting. Broker non-votes and abstentions from voting will have the same effect as voting against the William Penn merger proposal, but will have no effect on the William Penn adjournment proposal.

As of the record date, directors and executive officers of William Penn and their affiliates had the right to vote 785,058 shares of William Penn common stock, or approximately 8.5% of the outstanding William Penn common stock entitled to be voted at the special meeting. Each of the directors and executive officers of William Penn has entered into a separate voting agreement with Mid Penn, pursuant to which each such director and executive officer has agreed to vote all shares of William Penn common stock over which he or she has the sole power to vote or direct the voting thereof in favor of the William Penn merger proposal and certain related matters and against alternative transactions.

William Penn Shareholders Will Receive Shares of Mid Penn Common Stock in the Merger (page 92).

Upon completion of the merger, each outstanding share of William Penn common stock outstanding immediately prior to the effective time of the merger will be converted into the right to receive 0.426 shares of Mid Penn common stock, which we refer to as the “merger consideration.” The exchange ratio is fixed and not subject to adjustment, except in limited circumstances.

On October 31, 2024, which was the last trading date preceding the public announcement of the proposed merger, the closing price of Mid Penn common stock was $31.59 per share. On February 6, 2025, the most recent practicable trading day prior to the printing of this joint proxy statement/prospectus, the closing price of Mid Penn common stock was $30.28 per share. The market price of both Mid Penn common stock and William Penn common stock will fluctuate before the completion of the merger; therefore, you are urged to obtain current market quotations for Mid Penn common stock and William Penn common stock. The value of the merger consideration will fluctuate as the market price of Mid Penn common stock fluctuates before the completion of the merger. The market price of Mid Penn common stock at closing will not be known at the time of the William Penn special meeting and may be more or less than the current price of Mid Penn common stock or the price of Mid Penn common stock at the time of the William Penn special meeting or at the effective time of the merger.

Expected Material United States Federal Income Tax Treatment as a Result of the Merger (page 108)

The merger is structured to be treated as a reorganization for U.S. federal income tax purposes. Each of Mid Penn and William Penn has conditioned the consummation of the merger on its receipt of a legal opinion that this will be the case. Because William Penn shareholders will receive solely Mid Penn common stock for their shares (except for cash in lieu of fractional shares), William Penn shareholders should not recognize gain or loss except with respect to the cash they receive instead of a fractional share.

This U.S. federal income tax treatment may not apply to all William Penn shareholders. Determining the actual tax consequences of the merger to William Penn shareholders can be complicated. William Penn shareholders should consult their own tax advisor for a full understanding of the merger’s tax consequences that are particular to each shareholder.

Exceptions to these conclusions or other considerations may apply, some of which are discussed beginning on page 110. Determining the actual tax consequences of the merger to a William Penn shareholder can be complicated. For further information, please refer to “Material United States Federal Income Tax Consequences

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of the Merger” on page 108. William Penn shareholders should also consult their own tax advisors for a full understanding of the U.S. federal income tax and other tax consequences of the merger as they apply specifically to them.

Accounting Treatment of the Merger (page 107)

Mid Penn will account for this transaction as a business combination under the acquisition method. On the acquisition date, Mid Penn will record at fair value the identifiable assets acquired and the liabilities assumed, any noncontrolling interest, and goodwill (or a gain from a bargain purchase). The results of operations for the combined company will be reported prospectively subsequent to the acquisition date.

Market Prices and Share Information

Mid Penn common stock is listed on The Nasdaq Global Market under the symbol “MPB.” William Penn common stock is quoted on the Nasdaq Capital Market under the symbol “WMPN.”

The table below shows the last sale price of Mid Penn common stock and William Penn common stock, and the value of Mid Penn common stock received per share of William Penn common stock based upon the exchange ratio, on October 31, 2024 (the last full trading day prior to announcement of the execution of the merger agreement) and February 6, 2025 (the latest practicable trading day prior to the date of these materials).

Because the exchange ratio is fixed and will be adjusted only in limited circumstances, including if Mid Penn declares any stock dividends or effects a stock split or reverse stock split, and the market price of Mid Penn common stock will fluctuate prior to the merger, the pro forma equivalent price per share of William Penn common stock will also fluctuate prior to the merger. William Penn shareholders will not know the final equivalent price per share of William Penn common stock when they vote on the merger. This information relates to the value of shares of William Penn common stock that will be converted into shares of Mid Penn common stock in the merger. You should obtain current stock price quotations for the shares.

Following completion of the merger, current Mid Penn shareholders will own in the aggregate approximately 83.15% of the outstanding shares of Mid Penn common stock and William Penn shareholders will own approximately 16.85% of the outstanding shares of Mid Penn common stock.

Opinion of William Penn’s Financial Advisor (page 57)

At the October 31, 2024 meeting at which the William Penn board of directors considered and approved the merger agreement, William Penn’s financial advisor, Piper Sandler & Co., or Piper Sandler, delivered its oral opinion to William Penn’s board of directors, which was subsequently confirmed in writing, to the effect that, as of October 31, 2024, subject to the procedures followed, assumptions made, matters considered and qualifications and limitations described in Piper Sandler’s opinion, the exchange ratio was fair, from a financial point of view, to William Penn common equity shareholders.

The full text of Piper Sandler’s opinion is attached as Annex B to this joint proxy statement/prospectus. The opinion outlines the procedures followed, assumptions made, matters considered and qualifications and limitations on the review undertaken by Piper Sandler in rendering its opinion.

William Penn shareholders should read the opinion and the summary description of Piper Sandler’s opinion contained in this joint proxy statement/prospectus carefully in their entirety.

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Piper Sandler’s opinion speaks only as of the date of the opinion. The opinion of Piper Sandler does not reflect any developments that may have occurred or may occur after the date of its opinion and prior to the completion of the merger. William Penn does not expect that it will request an updated opinion from Piper Sandler. The opinion was directed to William Penn’s board of directors in connection with its consideration of the merger and is directed only as to the fairness, from a financial point of view, of the merger consideration to William Penn common equity shareholders. Piper Sandler’s opinion does not constitute a recommendation to any William Penn shareholder as to how such shareholder should vote at any meeting of shareholders called to consider and vote upon the William Penn merger proposal. Piper Sandler’s opinion does not address the underlying business decision of William Penn to engage in the merger, the form or structure of the merger, the relative merits of the merger as compared to any other alternative business strategies that might exist for William Penn or the effect of any other transaction in which William Penn might engage. Piper Sandler did not express any opinion as to the fairness of the amount or nature of the compensation to be received in the merger by William Penn’s officers, directors, or employees, or class of such persons, if any, relative to the compensation to be received in the merger by any other shareholder of William Penn.

For further information, see “The Merger—Opinion of William Penn’s Financial Advisor.”

Opinion of Keefe, Bruyette & Woods, Inc. to Mid Penn’s Board of Directors (page 72)

In connection with the merger, Keefe, Bruyette & Woods, Inc., which we refer to as KBW, delivered a written opinion, dated October 31, 2024, to the Mid Penn board of directors as to the fairness, from a financial point of view and as of the date of the opinion, to Mid Penn of the exchange ratio in the proposed merger. KBW was retained by Mid Penn solely to render its opinion to the Mid Penn board of directors. The full text of KBW’s opinion, which describes the procedures followed, assumptions made, matters considered, and qualifications and limitations on the review undertaken by KBW in preparing the opinion, is attached as Annex C to this joint proxy statement and prospectus. The opinion was for the information of, and was directed to, the Mid Penn board of directors (in its capacity as such) in connection with its consideration of the financial terms of the merger. The opinion did not address the underlying business decision of Mid Penn to engage in the merger or enter into the merger agreement or constitute a recommendation to the Mid Penn board of directors in connection with the merger, and it does not constitute a recommendation to any holder of Mid Penn common stock or any shareholder of any other entity as to how to vote in connection with the merger or any other matter.

For further information, see “The Merger—Opinion of Keefe, Bruyette & Woods, Inc. to Mid Penn’s Board of Directors.”

Board of Directors and Executive Officers of Mid Penn after the Merger (page 87)

Following completion of the merger, the then current directors and executive officers of Mid Penn and Mid Penn Bank will continue in office. In addition, upon the effective time of the merger, Kenneth J. Stephon, the current Chairman, President and Chief Executive Officer of William Penn, will be appointed as (i) a director of Mid Penn and Mid Penn Bank, (ii) Vice Chair of Mid Penn Bank, and (iii) Chief Corporate Development Officer of Mid Penn and Mid Penn Bank. The remaining directors of William Penn serving on the William Penn board of directors at the effective time of the merger will be appointed to a paid three-year advisory board of Mid Penn following completion of the merger.

The Mid Penn Board of Directors Recommends That Mid Penn Shareholders Vote “FOR” the Mid Penn Share Issuance Proposal (page 72)

The Mid Penn board of directors believes that the merger is in the best interests of Mid Penn and its shareholders and has unanimously approved the merger and the merger agreement. The Mid Penn board of directors recommends that Mid Penn shareholders vote “FOR” approval of the Mid Penn share issuance proposal. The Mid Penn board also recommends that its shareholders vote “FOR” the Mid Penn adjournment proposal.

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The William Penn Board of Directors Recommends That William Penn Shareholders Vote “FOR” the William Penn Merger Proposal (page 57)

The William Penn board of directors believes that the merger is in the best interests of William Penn and its shareholders and has unanimously approved the merger and the merger agreement. The William Penn board of directors recommends that William Penn shareholders vote “FOR” the William Penn merger proposal. The William Penn board also recommends that its shareholders vote “FOR” the William Penn adjournment proposal.

William Penn’s Directors and Executive Officers Have Financial Interests in the Merger that May Differ from the Interests of William Penn Shareholders (page 89)

In addition to their interests as William Penn shareholders, the directors and certain executive officers of William Penn have interests in the merger that are different from or in addition to interests of other William Penn shareholders. These interests include, among other things:

William Penn’s board of directors was aware of these interests and took them into account in its decision to approve the merger agreement. For information concerning these interests, please see the discussion on page 89

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under the caption “Interests of William Penn’s Directors and Executive Officers in the Merger.” For more information concerning the closing conditions of the merger, please see the discussion on page 96 under the caption “The Merger Agreement—Covenants and Agreements.”

The Rights of William Penn Shareholders Will Change After the Merger (page 120)

The rights of William Penn shareholders will change as a result of the merger due to differences in Mid Penn’s and William Penn’s governing documents. The rights of William Penn’s shareholders are governed under Maryland law and by William Penn’s articles of incorporation and bylaws. Upon completion of the merger, the rights of William Penn shareholders will be governed under Pennsylvania law and by Mid Penn’s articles of incorporation and bylaws. A description of shareholder rights under each of the Mid Penn and William Penn governing documents, and the material differences between them, is included in the section entitled “Comparison of Shareholders’ Rights” found on page 120.

Conditions That Must Be Satisfied or Waived for the Merger to Occur (page 103)

Currently, we expect to complete the merger in the second quarter of 2025. In addition to the approval of the merger proposal by the requisite vote of William Penn shareholders, the approval of the share issuance by the requisite vote of Mid Penn shareholders and the receipt of all required regulatory approvals and expiration or termination of all statutory waiting periods in respect thereof, each as described herein, each party’s obligation to complete the merger is also subject to the satisfaction or waiver (to the extent permitted under applicable law) of certain other conditions, including the effectiveness of the registration statement containing this joint proxy statement/prospectus, approval of the listing on the Nasdaq Stock Market of the Mid Penn common stock to be issued in the merger, the absence of any applicable law or order prohibiting the merger, the accuracy of the representations and warranties of the other party under the merger agreement (subject to the materiality standards set forth in the merger agreement), the performance by the other party of its respective obligations under the merger agreement in all material respects, delivery of officer’s certificates by the other party certifying satisfaction of the two preceding conditions and each of Mid Penn’s and William Penn’s receipt of a tax opinion to the effect that the merger will be treated as a “reorganization” within the meaning of Section 368(a) of the Internal Revenue Code.

Neither William Penn nor Mid Penn can be certain when, or if, the conditions to the merger will be satisfied or waived, or that the merger will be completed.

No Solicitation of Other Offers (page 100)

William Penn has agreed that it will not, and that it will cause its subsidiaries not, and use its reasonable best efforts to cause each of their respective officers, directors, employees, representatives, agents, and affiliates not to, except as otherwise expressly permitted in the merger agreement, between the date of the merger agreement and the closing of the merger, directly or indirectly:

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The merger agreement does not, however, prohibit William Penn from furnishing information or access to a third party who has made an unsolicited alternative acquisition proposal and participating in discussions and negotiating with such person if specified conditions are met. Among those conditions is a good faith determination by William Penn’s board of directors, after consultation with and having considered the advice of its outside legal counsel and its independent financial advisor, that the unsolicited alternative acquisition proposal constitutes, or is reasonably likely to lead to, a proposal that is more favorable, from a financial point of view, to William Penn and its shareholders than the transactions contemplated by the merger agreement and is reasonably capable of being completed on its stated terms, taking into account all financial, regulatory, legal and other aspects of the proposal.

For further discussion of the restrictions on solicitation of acquisition proposals from third parties, see “The Merger Agreement—Agreement Not to Solicit Other Offers” beginning on page 100.

Termination of the Merger Agreement (page 104)

Mid Penn and William Penn may mutually agree to terminate the merger agreement before completing the merger, even after William Penn or Mid Penn shareholder approval. In addition, either Mid Penn or William Penn may decide to terminate the merger agreement, if (i) a court or governmental entity issues a final order that is not appealable prohibiting the merger, (ii) a bank regulator which must grant a regulatory approval as a condition to the merger denies such approval of the merger, and such denial has become final and is not appealable, or imposes a materially burdensome regulatory condition in connection with the approval of the merger, (iii) the shareholders of William Penn fail to approve the merger at the special meeting; (iv) the shareholders of Mid Penn fail to approve the issuance of shares of Mid Penn common stock to holders of William Penn shareholders in connection with the merger at the special meeting, or (v) the other party breaches the merger agreement in a way that would entitle the party seeking to terminate the agreement not to consummate the merger, subject to the right of the breaching party to cure the breach within thirty (30) days following written notice. Either of Mid Penn or William Penn may also terminate the merger agreement if the merger has not been completed by December 1, 2025, unless the reason the merger has not been completed by that date is a breach of the merger agreement by the company seeking to terminate the merger agreement.

Mid Penn may terminate the merger agreement if the William Penn board of directors, in connection with the receipt of a superior alternative acquisition proposal, (1) enters into a letter of intent, agreement in principle or an acquisition agreement with respect to the superior alternative acquisition proposal, (2) fails to make, withdraws, modifies or qualifies its recommendation that William Penn shareholders approve the merger agreement in a manner adverse to Mid Penn, or (3) has otherwise made a determination to accept the superior alternative acquisition proposal.

William Penn may terminate the merger agreement if William Penn receives an alternative acquisition proposal and the William Penn board of directors has made a determination that the alternative acquisition proposal is a superior proposal and accepts such alternative acquisition proposal.

William Penn may also terminate the merger agreement on or after the fifth business day immediately prior to the closing date of the merger (the “determination date”) if the quotient obtained by dividing (A) the average of the per share closing price of a share of Mid Penn common stock during the twenty consecutive full trading days ending on the trading day prior to the determination date by (B) $30.59 causes the financial price ratio to be both (i) less than 0.80, and (ii) less than (by more than 20%) the quotient obtained by dividing (Y) the Dow Jones U.S. Micro Cap Banks Index Value during the twenty consecutive full trading days ending on the trading day prior to the determination date by (Z) $31,420.39. If William Penn chooses to exercise this termination right, Mid Penn has the option, within two business days of receipt of written notice from William Penn, to adjust the exchange ratio and prevent termination of the merger agreement.

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Termination Fee (page 105)

William Penn will pay Mid Penn a termination fee of $4,900,000 if the merger agreement is terminated:

William Penn will also be required to pay Mid Penn the termination fee of $4,900,000 in the event that William Penn enters into a definitive agreement relating to, or consummates, an acquisition proposal within twelve (12) months following termination of the merger agreement:

Regulatory Approvals Required for the Merger (page 88)

Completion of the merger and the bank merger are subject to the receipt of all approvals required by, or waivers from, applicable regulatory authorities and the absence of any materially burdensome regulatory condition imposed in connection with any such regulatory approval. The transaction is subject to approval by the Federal Deposit Insurance Corporation (the “FDIC”) and the Pennsylvania Department of Banking and Securities (the “PDB”) and approval, or waiver of formal application and approval requirements, from the Board of Governors of the Federal Reserve System (the “FRB”). Mid Penn has filed or will file all required applications, notices and waiver requests to obtain the regulatory approvals and non-objections necessary to consummate the merger. While Mid Penn does not know of any reason why it would not obtain the approvals in a timely manner, Mid Penn cannot be certain when or if it will receive the required regulatory approvals or that any such approvals received will not include a materially burdensome regulatory condition.

Notifications and/or applications requesting approval may also be submitted to various other federal and state regulatory authorities and self-regulatory organizations. Mid Penn and William Penn have agreed to use their reasonable best efforts to obtain all required regulatory approvals.

Risk Factors (page 39)

You should consider all the information contained in or incorporated by reference into this joint proxy statement/prospectus in deciding how to vote for the proposals presented in the joint proxy statement/prospectus. In particular, you should consider the factors described under “Risk Factors.”

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UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS AND PER SHARE DATA

The unaudited pro forma combined condensed consolidated financial information has been prepared using the acquisition method of accounting under the provisions of the Financial Accounting Standards Board Accounting Standards Codification 805, “Business Combinations”, giving effect to the proposed merger of William Penn with and into Mid Penn, with Mid Penn as the surviving corporation. Under this method, William Penn assets and liabilities as of the date of the acquisition will be recorded at their respective fair values and added to those of Mid Penn. Any difference between the purchase price for William Penn and the fair value of the identifiable net assets acquired (including core deposit intangibles) will be recorded as goodwill. The goodwill resulting from the acquisition will not be amortized to expense but instead will be reviewed for impairment at least annually. Any core deposit intangible and other intangible assets with estimated useful lives to be recorded by Mid Penn in connection with the acquisition will be amortized to expense over such intangible asset’s estimated useful life. The financial statements of Mid Penn issued after the acquisition will reflect the results attributable to the acquired operations of William Penn beginning on the date of completion of the acquisition.

The following unaudited pro forma condensed combined financial information and accompanying notes are based on and should be read in conjunction with the following historical financial statements and accompanying notes, which are incorporated by reference into this filing:

The unaudited pro forma condensed combined financial information is provided for illustrative information purposes only. The unaudited pro forma condensed combined financial information is not necessarily, and should not be assumed to be, an indication of the actual results that would have been achieved had the merger been completed as of the dates indicated or that may be achieved in the future. The unaudited pro forma combined condensed financial statements have been prepared in accordance with Article 11 of Regulation S-X, Pro Forma Information, which requires the depiction of the accounting for the transaction, which we refer to as transaction accounting adjustments. Regulation S-X also allows for management adjustments that could include presentation of the reasonably estimable cost savings and revenue enhancements and other transaction effects that have occurred or are reasonably expected to occur. Mid Penn has elected to present one management adjustment giving effect to the previously reported November 5, 2024 consummation and issuance of 2,731,250 Mid Penn common shares at a price to the public of $29.50 per share and the receipt of net proceeds to Mid Penn of approximately $76.5 million as if it had been consummated on September 30, 2024, and will also be presenting transaction accounting adjustments in the following unaudited pro forma condensed combined financial information.

The following unaudited pro forma combined consolidated balance sheet as of September 30, 2024, combines the unaudited consolidated balance sheet of Mid Penn of September 30, 2024, with the unaudited statement of financial condition of William Penn as of September 30, 2024, giving effect to the transaction and the common stock offering as if it had been consummated on September 30, 2024. The unaudited pro forma condensed

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combined statements of income for the nine months ended September 30, 2024, combines the unaudited consolidated statements of income of Mid Penn for the nine months ended September 30, 2024, with the unaudited consolidated statement of income of William Penn for the nine months ended September 30, 2024, giving effect to the transaction and the common stock offering as if it had been consummated on January 1, 2023. The unaudited pro forma condensed combined statement of operations for the year ended December 31, 2023 combines the audited consolidated statements of income of Mid Penn for the year ended December 31, 2023 with the consolidated statements of income of William Penn for the year ended December 31, 2023, giving effect to the transaction and the common stock offering as if it had been consummated on January 1, 2024. Certain reclassification adjustments have been made to William Penn’s financial statements to conform to Mid Penn’s financial statement presentation.

Mid Penn and William Penn have different fiscal years. William Penn’s fiscal year ends on June 30 of each year and Mid Penn’s fiscal year ends on December 31 of each year. As the fiscal years differ by more than 93 days, pursuant to SEC rules, William Penn’s financial information was adjusted for the purpose of preparing the unaudited pro forma condensed statements of income. The historical income statement information of William Penn used in the unaudited pro forma condensed combined statements of income for the year ended December 31, 2023 was prepared by taking the audited condensed combined income statement for the year ended June 30, 2024, subtracting the unaudited condensed combined income statement for the six months ended June 30, 2024 and adding the unaudited condensed combined income statement for the six months ended June 30, 2023. The historical financial statement information of William Penn used in the unaudited pro forma condensed combined statements of income for the nine months ended September 30, 2024 was prepared by taking the audited condensed combined income statement for the twelve months ended June 30, 2024, subtracting the unaudited condensed combined income statement for the six months ended December 31, 2023, and adding the unaudited combined income statement for the three months ended September 30, 2024.

The unaudited pro forma condensed consolidated financial statements were prepared with Mid Penn as the accounting acquirer and William Penn as the accounting acquiree under the acquisition method of accounting. Accordingly, the consideration paid by Mid Penn to complete the acquisition of William Penn will be allocated to William Penn’s assets and liabilities based upon their estimated fair values as of the date of completion of the acquisition. The allocation is dependent upon certain valuations and other studies that have not been finalized at this time; however, preliminary significant valuations based on the fair value of the acquired assets and liabilities have been estimated and included in the unaudited condensed pro forma financial statements.

The final allocation of the purchase price will be determined after the merger is completed and after completion of thorough analyses to determine the fair value of William Penn’s tangible and identifiable intangible assets and liabilities as of the closing date. Increases or decreases in the estimated fair values of the net assets as compared with the information shown in the unaudited pro forma combined condensed consolidated financial information may change the amount of the purchase price allocated to goodwill and other assets and liabilities and may impact Mid Penn’s consolidated statements of income due to adjustments in yield and/or amortization of the adjusted assets or liabilities. Any changes to William Penn’s shareholders’ equity, including results of operations from September 30, 2024, through the closing date will also change the purchase price allocation, which may include the recording of a lower or higher amount of goodwill. The final adjustments may be materially different from the transaction accounting adjustments presented herein.

The pro forma statements of income and per share data information does not include anticipated cost savings or revenue enhancements. Mid Penn and William Penn are currently in the process of assessing the two companies’ personnel, benefits plans, premises, equipment, computer systems and service contracts to determine where the companies may take advantage of redundancies or where it will be beneficial or necessary to convert to one system. Certain decisions arising from these assessments may involve canceling contracts between either William Penn or Mid Penn and certain service providers. There is no assurance that the anticipated cost savings will be realized on the anticipated time schedule or at all.

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The pro forma combined basic and diluted earnings per share of Mid Penn common stock is based on the pro forma combined net income per common share for William Penn and Mid Penn divided by the pro forma basic or diluted common shares of the combined entities for the periods presented on such statements of income. The pro forma information includes adjustments related to the fair value of assets and liabilities of William Penn and is subject to adjustment as additional information becomes available and as final merger date analyses are performed. The pro forma combined balance sheet and book value per share data includes the impact of merger related expenses on the balance sheet with Mid Penn’s after-tax estimated charges of $9.3 million, illustrated as an adjustment to statements of income, retained earnings and to accrued other liabilities. The pro forma combined book value per share of Mid Penn common stock is based on the pro forma combined common stockholders’ equity of William Penn and Mid Penn divided by total pro forma common shares of the combined entities.

The unaudited pro forma data are qualified by the statements set forth under this caption and should not be considered indicative of the market value of Mid Penn common stock or the actual or future results of operations of Mid Penn for any period. Actual results may be materially different than the pro forma information presented.

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Mid Penn Bancorp, Inc.

Unaudited Combined Pro Forma Balance Sheets as of September 30, 2024

($ In thousands, except per share data)

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Unaudited Pro Forma Combined Statements of Income for nine months ended September 30, 2024

($ In Thousands, Except Per Share Data)

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Unaudited Pro Forma Combined Income Statement for twelve months ended December 31, 2023

($ In Thousands, Except Per Share Data)