SEC Form DEF 14A filed by Old Second Bancorp Inc.

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of

the Securities Exchange Act of 1934 (Amendment No.             )

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Old Second Bancorp, Inc.

(Name of Registrant as Specified In Its Charter)

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

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OLD SECOND BANCORP, INC.

37 South River Street, Aurora, Illinois 60507

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

TO BE HELD MAY 19, 2026

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TO OUR STOCKHOLDERS:

The annual meeting of stockholders of Old Second Bancorp, Inc., will be held on Tuesday, May 19, 2026, at 9:00 a.m., central time. This year’s meeting will be a completely virtual meeting of stockholders. You can attend the meeting via the Internet at www.virtualshareholdermeeting.com/OSBC2026 by using the 16-digit control number that appears in the notice or, if applicable, on your proxy card, together with the instructions in these proxy materials. This meeting will be held for the following purposes:

The board of directors is not aware of any other business to come before the meeting. Stockholders of record at the close of business on March 20, 2026 are the stockholders entitled to vote at the meeting and any and all adjournments or postponements of the meeting.

Whether or not you plan to virtually attend the annual meeting, we urge you to vote now to make sure there will be a quorum for the meeting. Voting by the Internet is fast and convenient, and your vote is immediately confirmed and tabulated. If you request or receive a paper copy of the proxy materials, you may also vote by completing, signing, dating and returning the proxy card provided with those materials. If you attend the meeting virtually over the Internet, you may continue to have your shares of common stock voted as instructed in a previously delivered proxy or you may vote your shares of common stock via the Internet during the meeting.

Important Notice Regarding the Availability of Proxy Materials for the 2026 Annual Meeting of Stockholders: Our Proxy Statement for the 2026 Annual Meeting of Stockholders, form of proxy and Annual Report to Stockholders for the fiscal year ended December 31, 2025 are available free of charge at www.proxyvote.com.

Aurora, Illinois

April 6, 2026

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OLD SECOND BANCORP, INC.

37 South River Street, Aurora, Illinois 60507

PROXY STATEMENT

This proxy statement is furnished in connection with the solicitation by the board of directors of Old Second Bancorp, Inc., a Delaware corporation, of proxies to be voted at the annual meeting of stockholders. This meeting is to be held virtually over the Internet, on May 19, 2026 at 9:00 a.m., central time, or at any postponements or adjournments of the meeting. Instructions for virtually attending the meeting are included below. Old Second Bancorp, Inc. conducts a full service community banking and trust business through its wholly owned subsidiary, Old Second National Bank. Our principal executive offices are located at 37 South River Street, Aurora, Illinois 60507.

Our annual report for the year ended December 31, 2025, which includes audited financial statements, accompanies these proxy materials for stockholders receiving printed materials and is available free of charge at www.proxyvote.com. This proxy statement was first mailed to our stockholders on or about April 6, 2026. As used in this proxy statement, the terms “Old Second,” “the Company,” “we,” “our” and “us” all refer to Old Second Bancorp, Inc., and its subsidiaries. Additionally, references to the “Bank” refer to Old Second National Bank.

GENERAL INFORMATION ABOUT THE MEETING AND VOTING

Why am I receiving these proxy materials?

You are receiving these proxy materials because, on March 20, 2026, the record date for the annual meeting, you owned shares of our common stock. These proxy materials describe the matters that will be presented for consideration by stockholders at the annual meeting and provide information to assist you in making an informed voting decision.

If you vote by Internet or, if you request or receive printed proxy materials, by signing, dating, and returning the proxy card provided with those materials, you will appoint the proxy holder as your representative at the meeting. The proxy holder will vote your shares as you have instructed, ensuring that your shares will be voted whether or not you attend the meeting. Even if you plan to attend the annual meeting, we urge you to vote in advance of the annual meeting in case your plans change.

What matters will be voted on at the meeting?

You are being asked to vote on three matters:

How does the board of directors recommend that I vote?

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How can I attend the annual meeting?

This year, the annual meeting will be held virtually over the Internet. We designed the format of this virtual annual meeting to ensure that our stockholders who attend our annual meeting will be afforded the same rights and opportunities to participate as they would at an in-person meeting. Our board members and executive officers will attend the meeting and be available for questions.

In accordance with Delaware law, a list of stockholders entitled to vote at the Annual Meeting will be open to examination by any stockholder, for any purpose germane to the Annual Meeting, for the ten days preceding the Annual Meeting during ordinary business hours at the Company’s principal place of business, 37 South River Street, Aurora, Illinois 60507.

Can I attend the annual meeting as a guest?

Yes. If you are not a stockholder or do not have a control number, you may join the meeting as a guest to listen, but you will not be able to participate.

How can I ask questions during the meeting?

Stockholders may submit questions in real time during the meeting at www.virtualshareholdermeeting.com/OSBC2026 by entering the 16-digit control number located in the notice or, if applicable, on your proxy card. We intend to respond to all questions submitted during the meeting in accordance with the annual meeting’s Rules of Conduct which are pertinent to the Company and the meeting matters, as time permits. The Rules of Conduct will be posted at the virtual annual meeting forum at www.virtualshareholdermeeting.com/OSBC2026. Responses to any such questions that are not addressed during the meeting will be published following the meeting on our website at www.oldsecond.com under the link “Investor Relations.” Questions and responses will be grouped by topic and substantially similar questions will be grouped and responded to once.

What can I do if I need technical assistance during the meeting?

If you encounter any difficulties accessing the virtual meeting during the check-in or meeting time, please call the technical support number that will be posted on the virtual annual meeting log-in page.

If I am a stockholder of record, how do I vote?

If you are a stockholder of record, you may:

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Regardless of whether you plan to participate in the audio webcast of the meeting, you are urged to vote via the Internet before the meeting or, if you request or receive printed proxy materials, by signing, dating and returning the proxy card provided with those materials. If you participate in the audio webcast, you may continue to have your shares of common stock voted as instructed in a previously delivered proxy.

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What does it mean if I receive more than one proxy form?

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It means that you have multiple holdings reflected in our stock transfer records and/or in accounts with stockbrokers. Please vote all notices, proxy cards and/or voting instruction forms you receive so that all of your shares are voted.

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If I hold shares in “street name” through a bank, broker or other nominee, how do I vote?

If you hold your shares in street name and you received this proxy statement from your bank, broker or other nominee (collectively, a “broker”), your broker will provide you with instructions for voting your shares. The availability of online voting during the meeting may depend on the voting procedures of the broker that holds your shares. If you have any questions about voting or your control number, please contact the broker that holds your shares.

What if I change my mind after I return my proxy?

If you are a stockholder of record, you may revoke your proxy and change your vote at any time before the polls close at the annual meeting. You may do this by:

If you hold your shares in street name and desire to revoke your proxy, you will need to contact your broker to revoke your proxy or change your vote.

What is a broker non-vote?

If you hold your shares in street name, your brokerage firm may vote your shares under certain circumstances. Brokerage firms have authority under stock exchange rules to vote their customers’ unvoted shares on certain “routine” matters. We expect that brokers will be allowed to exercise discretionary authority for beneficial owners who have not provided voting instructions ONLY with respect to Proposal 3, the ratification of Plante & Moran, PLLC as our independent registered public accounting firm for the year ending December 31, 2026, but not with respect to any of the other proposals to be voted on at the annual meeting. If you hold your shares in street name, please provide voting instructions to your broker so that your shares may be voted on all other proposals.

When a brokerage firm votes its customers’ unvoted shares on routine matters, these shares are counted for purposes of establishing a quorum to conduct business at the meeting. If a brokerage firm indicates on a proxy that it does not have discretionary authority to vote certain shares on a particular matter, then those shares will be treated as “broker non-votes” but will still be counted for quorum purposes.

What is the quorum requirement for the annual meeting?

We will have a quorum and will be able to conduct the business of the annual meeting if the holders of a majority of our issued and outstanding shares entitled to vote are present in person or by proxy at the annual meeting. On March 20, 2026, the record date, we had 51,779,472 shares of common stock issued and outstanding. Abstentions and broker non-votes are counted as shares present at the meeting for purposes of determining a quorum. Shares will be counted for quorum purposes if they are represented at the meeting for any purpose other than solely to object to holding the meeting or transacting business at the meeting.

How many votes may I cast?

You are entitled to cast one vote for each share of common stock you owned on the record date with respect to each of the proposals. Stockholders do not have cumulative voting rights. If you request or receive printed proxy materials, the proxy card provided with those materials indicates the number of shares attributable to your account.

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What happens if any nominee is unable to stand for re-election?

The board may, by resolution, provide for a lesser number of directors or designate a substitute nominee. In the latter case, shares represented by proxies may be voted for a substitute nominee. Proxies cannot be voted for more than four nominees. The board has no reason to believe any nominee will be unable to stand for re-election.

What is the required vote for each proposal?

Assuming a quorum is present, the required vote for each proposal is as follows:

For each proposal, this means that the number of votes cast “FOR” each proposal must exceed the number of votes cast “AGAINST” and/or “ABSTAIN” with respect to that proposal. This includes the proposal regarding the election of directors in accordance with the policy of majority voting in uncontested director elections set forth in our bylaws.

Broker non-votes will not affect the outcome of voting on a particular proposal, and abstentions will have the effect of a vote against the applicable proposal, or, in the election of directors, against the applicable nominee.

Please note that, because the say-on-pay vote is advisory, it will not be binding upon our board of directors or our Compensation Committee.

All valid proxies that we receive will be voted in accordance with the instructions indicated in such proxies. As noted above, if you hold your shares in street name through a broker and you do not give voting instructions, your broker is not permitted to vote your shares on any proposal other than Proposal 3, which is the only routine proposal on the agenda. If no instructions are indicated in an otherwise properly executed proxy card or voting instruction form, it will be voted “FOR” each of the Class I director nominees named in this proxy statement, “FOR” the say-on-pay proposal, and “FOR” the ratification of Plante & Moran, PLLC as our independent registered public accounting firm for 2026. If any other matters are presented at the annual meeting, the persons named as proxies in the proxy card or voting instruction form will have discretionary authority to vote for you on those matters.

Where do I find the voting results for the annual meeting?

If available, we will announce preliminary voting results at the meeting. The voting results will also be disclosed in a Form 8-K filed with the U.S. Securities and Exchange Commission (the “SEC”) within four business days of the meeting.

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PROPOSAL 1:

ELECTION OF DIRECTORS

Our board of directors is divided into three classes equal in number, serving staggered three-year terms. As a result, the terms of only approximately one-third of our board members expire at each annual meeting. The current term of our Class I directors will expire at this year’s annual meeting. The term of our Class II directors will expire at the 2027 annual meeting and the term of our Class III directors will expire at the 2028 annual meeting.

Each proposed Class I director nominee currently serves as a Class I director.

Following a review and nomination from our Corporate Governance and Nominating Committee, our board has proposed that the following Class I directors be elected as Class I directors at our 2026 annual meeting of stockholders for a term that will expire at our 2029 annual meeting and until their respective successors are duly elected and qualified.

Class I Director Nominees

Each Class I director nominee will be elected if the number of shares voted “FOR” the nominee constitutes a majority of the shares having voting power present in person or represented by proxy at the annual meeting. Accordingly, broker non-votes will not have any effect on the outcome of voting, but abstentions will have the effect of a vote “AGAINST” the applicable nominee.

There is no cumulative voting with respect to the election of directors.

The board of directors recommends that you vote “FOR” each of the above Class I director nominees.

Set forth below is information concerning our other directors, whose term of office will continue after the annual meeting, including their age and year first elected or appointed as a director.

Continuing Directors

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All directors will hold office for the terms indicated, or until their earlier death, resignation, removal or disqualification and until their respective successors are duly elected and qualified.

There are no arrangements or understandings between any of the nominees, directors or executive officers and any other person pursuant to which any of our nominees, directors or executive officers have been selected for their respective positions.

No nominee, member of the board of directors or executive officer is related to any other nominee, member of the board of directors or executive officer.

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Director Experience

Biographical information regarding each of our director nominees and continuing directors is set forth below, including the particular experience, qualifications, attributes or skills that led the board to conclude that each member is qualified to serve on the board and any committee he or she serves.

Mr. Bonifas:  Mr. Bonifas is an Executive Officer and Board Member of Alarm Detection Systems, Inc., a producer and installer of alarm systems, closed circuit video systems and card access control systems, a position he has held since 2000. We consider Mr. Bonifas to be qualified for service on the board, Nominating and Corporate Governance Committee, and the Risk and Insurance Committee due to his skills and expertise acquired as a leader of a successful business and his prominence in the communities we serve. Mr. Bonifas also serves on our Executive Committee and as Vice Chair of the Information Technology Steering committee where he uses his business expertise for cybersecurity oversight.

Mr. Campbell:  Mr. Campbell is the former President, CEO and Chairman of Evergreen Bank Group and its holding company, Bancorp Financial, Inc., which we acquired in July 2025. Mr. Campbell founded Evergreen Bank in 2007. Prior to 2007, Mr. Campbell served as a Senior Executive at Oak Brook Bank for 12 years until it was acquired by MB Financial, Inc. Mr. Campbell has over 31 years of banking and financial experience with a B.S. degree in Business and Finance. We consider Mr. Campbell to be qualified for service on the board and the Risk and Insurance Committee due to his skills and expertise acquired as a leader in the financial services industry. Mr. Campbell also serves on our Capital Committee and Executive Committee.

Mr. Collins:  Mr. Collins has served as our Vice Chairman since October 2016. Before that, he was Vice Chairman of Talmer Bancorp, Inc., a publicly traded bank holding company (formerly, NASDAQ: TLMR), from 2011 until 2016. He also served as a director of Talmer Bancorp, Inc. from 2010 until 2016. Mr. Collins served as Chairman and Co-Chief Executive Officer of Lake Shore Wisconsin Corporation, a bank holding company, from 2010 until 2011, and as a founding Managing Director and Vice Chairman of The Private Bank — Chicago from 1991 until 2009. We consider Mr. Collins to be qualified for service on the board due to his experience focused within mortgage banking and real estate opportunities among residential, multi-family, and commercial lending. Mr. Collins serves on the Capital Committee, as Vice Chair of the Executive Committee, and a member of the Information Technology Steering Committee, Loan Committee and Risk and Insurance Committee.

Mr. Eccher:  Mr. Eccher is our Chairman, President and Chief Executive Officer of the Company. Mr. Eccher was appointed as Chairman in May 2022. Mr. Eccher has also served as our President and Chief Executive Officer of the Bank since 2003. Mr. Eccher has previously served as Senior Vice President and Branch Director of the Bank from 1999 until 2003. Before that, he served as President and Chief Executive Officer of the Bank of Sugar Grove from 1996 until 1999. We consider Mr. Eccher to be qualified for service on the board due to his experience in the financial services industry and his familiarity with our operations. Mr. Eccher serves as Chair of the Capital Committee, as Chair of the Executive Committee, as Chair of the Loan Committee and on the Risk and Insurance Committee.

Mr. Finn:  Mr. Finn served as the President and Chief Executive Officer of Rush-Copley Medical Center from 2002 until his retirement in 2019. Before that, Mr. Finn served as the Chief Operating Officer and Chief Financial Officer of Rush-Copley Medical Center from 1996 until 2002. We consider Mr. Finn to be a qualified candidate for service on the board, including as our Lead Director, and the Nominating and Corporate Governance Committee as Chair, as well as a member of our Audit Committee, Compensation Committee, Executive Committee, Capital Committee, Information Technology Steering Committee, and the Loan Committee due to his business and financial expertise acquired as an executive at a successful local medical center, as well as his prominence in the communities we serve.

Mr. Klaeser:  Mr. Klaeser most recently served as a Strategic Advisor to TCF Financial Corporation (formerly, NASDAQ: TCF) from October 2020, until his retirement in June 2021. Before that, he served as Chief Financial Officer of TCF Financial Corporation (formerly Chemical Financial Corporation) and TCF National Bank from August 2016 until April 2020. Prior to his time at TCF Financial Corporation, Mr. Klaeser served as Chief Financial Officer and an Executive Managing Director of Talmer Bancorp, Inc. from May 2010 until Talmer Bancorp’s merger with Chemical Financial Corporation in August 2016. Mr. Klaeser also served as Chief Financial Officer and a director of First Place Bank following its acquisition by Talmer Bancorp, Inc. from January 2013 until it was merged into Talmer Bank and Trust in February 2014. Mr. Klaeser was a senior Midwest bank analyst with Raymond James from April 2009 to May 2010. From 2003 until 2009, Mr. Klaeser was Chief Financial Officer of PrivateBancorp, Inc. From 2000 through 2002, Mr. Klaeser was Managing Director and Head of the Financial Institutions Group for Anderson Corporate Finance, a division of Arthur Andersen, where he was responsible for advising financial institutions on complex merger and acquisition transactions, restructuring, and divestures. Mr. Klaeser also spent seven years as an investment banker and was head of the Financial Institutions Group at EVEREN Securities, which was acquired by First Union Securities. We consider Mr. Klaeser to be a qualified candidate for service on the board, as Vice Chair of the Audit Committee, a member of the Capital Committee, as Vice Chair of the Compensation Committee, and a member of the Executive Committee and the Risk and Insurance Committee due to his extensive executive-level experience in the financial services industry, including his service as a Chief Financial Officer for a public company.

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Mr. Kotche:  Mr. Kotche is a former partner at the law firm Levato & Kotche, a position he held from 1984 until his retirement in 2023. Before our acquisition of West Suburban Bancorp, Inc. (formerly, NASDAQ: WNRP), he served as a director of West Suburban Bancorp, Inc. and West Suburban Bank since 2010. He previously served on the board of STC Bancshares Corp. and STC Capital Bank from 2007 until they were sold to Wintrust in 2019. He also served on the board of Advantage National Bank (both Bank and Holding Company) from 2001 until they were sold to Wintrust in 2003. We consider Mr. Kotche to be a qualified candidate for service on the board, the Compensation Committee, the Loan Committee, the Nominating and Corporate Governance Committee, and as Vice Chair of the Risk and Insurance Committee due to his experience in law and business, 26 years of bank board experience, and his extensive knowledge of the market areas we serve, including the markets we entered through our acquisition of West Suburban.

Mr. Lyons:  Mr. Lyons served for over 30 years with the Office of the Comptroller of the Currency, most recently as a National Bank Examiner, before his retirement in December 2019. We consider Mr. Lyons to be a qualified candidate for service on the board and the Audit Committee, the Executive Committee, the Loan Committee, the Nominating and Corporate Governance Committee, and as Chair of the Risk and Insurance Committee due to his extensive bank regulatory and bank supervision experience with the bank’s primary federal regulator.

Mr. McLean:  Mr. McLean has been a Partner with Rock Island Capital since November 2016. Before that, Mr. McLean served as Regional President and Managing Director of Talmer Bank from 2010 until October 2016. From 2009 until 2010, he was President and Director of Lake Shore Wisconsin Corporation. Mr. McLean was Vice Chairman of The PrivateBank, a publicly traded commercial bank headquartered in Chicago, from 2001 until 2008, and was a Managing Director of The PrivateBank from 1996 until 2001. He also held senior commercial banking positions with Firstar Bank and American National Bank prior to joining the PrivateBank in 1996. We consider Mr. McLean to be a qualified candidate for service on the board, the Audit Committee, Capital Committee, Compensation Committee as Chair, Information Technology Steering Committee, and the Loan Committee due to his previous experience in the financial industry.

Ms. Temple Rocks:  Ms. Temple Rocks is currently the head of Temple Rocks IMC, a marketing consulting firm. Previously, her four-decade career included C-suite leadership roles for global marketing agencies including ICF Next, Golin and Leo Burnett. She was also the Chief Communications Officer for The Dow Chemical Company. We consider Ms. Temple Rocks to be a qualified candidate for service on the board, as Chair of the Information Technology Steering Committee, and a member of the Risk and Insurance Committee due to her business experience and familiarity with the greater Chicago market.

Mr. Williams:  Mr. Williams is Vice President of Bracing Systems, Inc., a construction supply and equipment supplier of masonry and concrete specialties, a position he has held since 1976. Before our acquisition of West Suburban Bancorp, Inc. (formerly, NASDAQ: WNRP), he served as director of West Suburban Bancorp, Inc. and West Suburban Bank since 1986. We consider Mr. Williams to be a qualified candidate for service on the board and the Risk and Insurance Committee due to his experience in business, as well as his extensive knowledge of the market areas we serve, including the markets we entered through our acquisition of West Suburban.

Ms. York:  Ms. York most recently served as President, Head of Equipment Finance and Leasing Solutions for Fifth Third Bank, until her retirement in April 2020. Before that, she held various executive level positions with MB Financial Inc. (formerly, NASDAQ: MBFI), including serving as its Chief Financial Officer, and its Vice President and Executive Vice President, Specialty Banking and Mergers and Acquisitions, of its subsidiary bank, until it was sold to Fifth Third Bank in March 2019. We consider Ms. York to be a qualified candidate for service on the board, as Chair of the Audit Committee, and a member of the Capital Committee, Compensation Committee, the Executive Committee, the Information Technology Steering Committee, and the Risk and Insurance Committee due to her extensive executive-level experience in the banking industry, including her service as a Chief Financial Officer for a public company.

Biographical Information for Executive Officers

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Because each of Mr. Eccher, Mr. Campbell, and Mr. Collins also serves on our board of directors, we have provided biographical information for them above. Biographical information for each of Mr. Adams and Mr. Pilmer is provided below:

Mr. Adams, age 52, joined the Company and the Bank in May 2017 to serve as an Executive Vice President and our Chief Financial Officer. Since August 2023, Mr. Adams also serves as the Chief Operating Officer of the Company and the Bank. From November 2016 until joining us, he served as Executive Vice President and Director of Corporate Development and Strategy for TCF National Bank, where he oversaw corporate development and strategy. Before that, he served as Executive Managing Director, Corporate Development, of Talmer Bancorp, Inc. from 2011 until 2016. While at Talmer, Mr. Adams was responsible for management of internal financial reporting, budgeting, mortgage bank accounting, investor relations, strategic planning and corporate development activities. Prior to joining Talmer, Mr. Adams also held positions as Managing Director of W2 Freedom, LLC, a private investment fund manager focused on investing in community banks, and as Director of Investor Relations for Fifth Third Bancorp. Mr. Adams serves as a member of the Information Technology Steering Committee and the Risk and Insurance Committee, which are both Bank-level committees.

Mr. Pilmer, age 61, joined the Company and the Bank in 1989. He currently serves as Executive Vice President (a position he has held since 2012) and as Chief Lending Officer (a position he has held since 2016). Mr. Pilmer manages the Commercial Banking unit and has more than 30 years of experience in the Commercial Banking industry.

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CORPORATE GOVERNANCE AND THE BOARD OF DIRECTORS

General

Currently, the board of directors is made up of twelve directors, one-third of whom are elected by the holders of our common stock every three years to serve staggered terms. In accordance with our corporate governance procedures, the board does not involve itself in our day-to-day operations, which are monitored by our executive officers and management. Our directors fulfill their duties and responsibilities by attending regular meetings of the board and through committee membership, which is discussed below.

Director Attendance

The board of directors held four regularly scheduled meetings during 2025, as well as additional meetings, as needed, to conduct the Company’s business. All of the directors attended at least 75% of these meetings and the meetings of the committees on which they served. We typically schedule a board meeting in conjunction with our annual meeting and expect that our directors will attend our annual meeting. Last year, all of our then-serving directors attended our annual meeting. We expect each director to attend our annual meetings of stockholders, although we recognize that conflicts may occasionally arise that will prevent a director from attending an annual meeting.

Code of Business Conduct and Ethics

The board of directors believes that it is important to encourage the highest level of corporate ethics and responsibility. Among other things, the board adopted a Code of Business Conduct and Ethics, which applies to all of our directors, officers and employees, as well as a procedure for allowing employees to anonymously report any problems they may detect with respect to our financial reporting. The Code of Business Conduct and Ethics, as well as other information pertaining to our committees, corporate governance and reporting with the SEC, can be found on our website at www.oldsecond.com, under the Investor Relations page, Governance, Governance Documents. We will post on our website any amendments to, or waiver from, the Code of Business Conduct and Ethics as it applies to any director or officer to the extent required to be disclosed by applicable NASDAQ or SEC requirements.

Director Independence

The board of directors has standing Audit, Nominating and Corporate Governance, and Compensation Committees, each of which is made up solely of directors who are deemed to be “independent” under the rules of NASDAQ. NASDAQ’s independence rules include certain instances that will preclude a director from being deemed independent and the board reviews those requirements each year to determine a director’s status as an independent director. The board has determined that all of the directors and nominees are “independent” as defined by the NASDAQ Stock Market, with the exception of Messrs. Eccher, Collins, and Campbell, each of whom is an executive officer.

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Board Resignation Policy

Our board of directors has adopted a resignation policy that provides that no person will be elected to serve, or will continue to serve, as a director of the Company after attaining age 73, and each director candidate or nominee has agreed that upon attaining age 73 during his or her tenure as director, the director will be deemed, effective at such time, to have resigned his or her directorship.

Our bylaws further provide that a nominee for director in an uncontested election will be elected by a majority of the shares having voting power present in person or represented by proxy at the meeting. Under our resignation policy, if a nominee receives more votes “against” his or her election than votes “for” his or her election, the director must promptly tender a written offer of resignation to the Chairman of the board of directors. Our Nominating and Corporate Governance Committee will promptly consider the director’s offer of resignation and recommend to the board of directors whether to accept or reject it. The board will act on the committee’s recommendation and will publicly disclose its decision within 120 days after the election results are certified.

Board Skills Matrix

Our board of directors collectively possesses deep experience across key disciplines that are critical to the strategic and operational oversight of the Company. The matrix below highlights the primary areas of expertise represented on the board. This disclosure reflects the board’s commitment to maintaining a well-rounded composition that supports effective governance, risk oversight, and long-term value creation for our shareholders.

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Committees of the Board of Directors

Actions taken by each committee of the board are reported to the full board, usually at its next meeting. The principal responsibilities of each of the committees are described below. Our board committees are currently composed as follows (M — member; C — chair):

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Current Board Committee Assignments

*Bank-level committee. In addition to those committee members listed above, Bank directors Bradley S. Adams and Jill Voss are members of the Information Technology Steering and the Risk and Insurance Committees.

Assuming the election or re-election of certain board members at the 2026 annual meeting of stockholders, the board committees will be composed as shown in the table above, with the addition of Darin Campbell as a member of the Loan Committee and Patti Temple Rocks as a member of the Nominating and Corporate Governance Committee.

Audit Committee

The Audit Committee assists the board in carrying out its oversight responsibilities for our financial reporting process, audit process and internal controls. The Audit Committee also oversees our internal audit function, including our charter, independence, resources, and activities, and receives regular reports from the Chief Audit Executive. The Audit Committee is solely responsible for the pre-approval of all required audit and non-audit services to be provided by our independent registered public accounting firm and exercises its authority to do so in accordance with a policy that it has adopted. The committee’s duties, responsibilities and functions are further described in its charter, which is available on our website at www.oldsecond.com, under the Investor Relations page, under the Governance tab,  and under the Governance Documents link. You can request a copy of the committee’s charter by sending a written request to the Corporate Secretary at 37 South River Street, Aurora, Illinois 60507, or by sending a request via e-mail to [email protected].

The members of our Audit Committee during 2025 were Ms. York (who serves as Chair), Mr. Finn, Mr. Klaeser, Mr. Ladowicz, who retired from the board September 2025, Mr. Lyons, and Mr. McLean. The board determined that each member of the committee was an independent director under SEC Rule 10A-3 and NASDAQ’s listing requirements. The Audit Committee met four times in 2025.

The board has designated each of Mr. Finn, Mr. Klaeser, and Ms. York as an “audit committee financial expert,” as such term is defined by the regulations of the SEC. The board believes that each of the other members of the Audit Committee possesses knowledge and experience sufficient to understand the complexities of our financial statements. Ms. York and other Audit Committee members met on a quarterly basis during 2025 with our independent registered public accounting firm.

To review our annual Audit Committee report, please see “Proposal 3 — Ratification of Our Independent Registered Public Accountants — Audit Committee Report.”

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Compensation Committee

The Compensation Committee reviews the performance of our executive officers and establishes their compensation levels. The committee also has the authority, among other things, to:

The committee’s duties, responsibilities and functions are described more fully in its charter, which is available on our website at www.oldsecond.com, under the Investor Relations page, under the Governance tab,  and under the Governance Documents link.  You can request a copy of the committee’s charter by sending a written request to the Corporate Secretary at 37 South River Street, Aurora, Illinois 60507, or by sending a request via e-mail to [email protected].

The members of our Compensation Committee during 2025 were Mr. McLean (who served as Chair), Mr. Finn, Mr. Klaeser, Mr. Kotche, Mr. Ladowicz, who retired from the board September 2025, and Ms. York. The board determined that each member of the committee was an independent director under NASDAQ’s listing requirements. The Compensation Committee met four times in 2025.

The Compensation Committee has the authority under its charter to select, or receive advice from, advisors, including compensation consultants. In 2025, the committee continued its engagement of McLagan, which is part of the Human Capital Solutions practice at Aon plc (“McLagan”), as independent advisors to assist the committee in determining and evaluating executive compensation. The Compensation Committee assessed the independence of McLagan taking into consideration all factors specified in NASDAQ listing standards. Based on this assessment, the Compensation Committee determined the engagement of McLagan did not raise any conflict of interest.

Nominating and Corporate Governance Committee

The Nominating and Corporate Governance Committee reviews the qualifications of, and recommends to the board for nomination, candidates to stand for election at each annual meeting or to fill vacancies on the board as they may occur during the year. The committee also reviews on at least an annual basis whether each director is “independent” under NASDAQ listing requirements. Additionally, the Nominating and Corporate Governance Committee is responsible for reviewing our policies, procedures and structure as they relate to corporate governance. The committee’s duties, responsibilities and functions are further described in its charter, which is available on our website at www.oldsecond.com, under the Investor Relations page, under the Governance tab, and under the Governance Documents link. You can request a copy of the committee’s charter by sending a written request to the Corporate Secretary at 37 South River Street, Aurora, Illinois 60507, or by sending a request via e-mail to [email protected].

The members of the Nominating and Corporate Governance Committee in 2025 were Mr. Finn (who serves as Chair), Mr. Bonifas, Mr. Kotche, Mr. Ladowicz, who retired from the board September 2025, and Mr. Lyons. The board determined that each member of the committee was an independent director under NASDAQ’s listing requirements. The Nominating and Corporate Governance Committee met once in 2025.

Board and Committee Evaluation Process

Under its charter, our Nominating and Corporate Governance Committee annually reviews and assesses the performance of our board of directors, including each committee of the board, and makes recommendations for areas of improvement as it deems appropriate. In this regard, the Nominating and Corporate Governance Committee also oversees an annual assessment of each director’s individual performance, which may be accomplished through a self-evaluation process. Each of the key committees of the board of directors (Audit, Compensation and Nominating and Corporate Governance) also performs an annual assessment of its performance and charter.

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Director Nominations and Qualifications

In making its nominations for persons to be elected to the board of directors and included in our proxy statement, the Nominating and Corporate Governance Committee evaluates incumbent directors, board nominees and persons nominated by stockholders, if any. The committee reviews each candidate in light of the criteria that we believe each director should possess. Included in the criteria are whether each nominee: (i) meets the minimum requirements for service on the board of directors contained in our bylaws; (ii) possesses the highest personal and professional ethics, integrity and values; (iii) has, in the committee’s opinion, a sufficient educational and professional background and relevant past and current employment affiliations, board affiliations and experience for service on the board; (iv) has demonstrated effective leadership and sound judgment in his or her professional life; (v) has a strong sense of service to the communities in which we serve; (vi) has exemplary management and communication skills; (vii) is free of conflicts of interest that would prevent him or her from serving on the board; (viii) will ensure that other existing and future commitments do not materially interfere with his or her service as a director; (ix) will review and agree to meet the standards and duties set forth in the Company’s Code of Business Conduct and Ethics; (x) is willing to devote sufficient time to carrying out their duties and responsibilities effectively; and (xi) is committed to serving on the board for an extended period of time. While we do not have a separate diversity policy, the committee does consider the diversity of its directors and nominees in terms of knowledge, experience, skills, expertise and other demographics which may contribute to the board. The committee also evaluates potential nominees to determine if they have any conflicts of interest that may interfere with their ability to serve as effective board members and to determine whether they are “independent” in accordance with NASDAQ requirements (to ensure that at least a majority of the directors will, at all times, be independent).

The committee, when considering potential board members, will look at all of the foregoing criteria. The various qualifications and criteria are normally considered by the committee in connection with its evaluation of who the committee will recommend as our director nominees. Generally, each incumbent director standing for re-election should have and will have, at a minimum, attended at least 75% of board meetings during the past year and attended 75% of committee meetings of which he or she is a member. The committee retains the ability to make exceptions to this attendance requirement as individual circumstances warrant.

All of the nominees for election as directors at the 2026 annual meeting were recommended for nomination by the committee. The committee did not receive any formal nominations for directors from our common stockholders.

Common Stock Ownership and Retention Guidelines for Non-Employee Directors

In order to align the interests of board members and stockholders, we require each non-employee director to develop a significant equity stake in the company. The Compensation Committee is responsible for monitoring compliance with these stock ownership and retention guidelines.

Non-employee directors are expected to acquire, and hold during their service as board members, shares of our common stock equal in value to at least three times the annual cash retainer for non-employee directors. Each non-employee director will have five years from the date they first become subject to these guidelines to achieve these target ownership levels. Individuals who acquire shares of common stock under our equity-based incentive plan must hold at least 50% of all net after-tax acquired shares until these stock ownership guidelines are satisfied.

The following share types are included under these guidelines: shares directly owned, family-owned shares, retirement plan shares and unvested time-based restricted stock. Stock options that are unexercised, regardless of their vesting status and in-the-money value, are not counted toward satisfaction of these guidelines. Unvested performance-based restricted stock is also not counted toward stock ownership.

All of our non-employee directors are currently in compliance with these guidelines.

Insider Trading Policy and Procedures

We maintain a comprehensive Insider Trading Policy that applies to all directors, officers, employees, and related persons of the Company and its subsidiaries. The policy is designed to promote compliance with federal securities laws and to prevent trading in Company securities while in possession of material nonpublic information. Further, it is also the policy of the Company to comply with all applicable securities laws when transacting in its own securities.

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Key features of the policy include:

The Insider Trading Policy is reviewed periodically and approved by the Board of Directors. It is filed as Exhibit 19.1 to the Company’s Form 10-K.

Family Relationships

There is no family relationship between any of our directors, nominees or executive officers, and there are no arrangements or understandings between the directors and any other person pursuant to which he or she was or is to be selected as a director or nominee.

Board Leadership Structure

Mr. Eccher currently serves as Chairman of the Board and as Chief Executive Officer and President of both the Company and the Bank, combining the roles of board leadership and executive management. We believe certain synergies are gained through the dual role of Chairman and Chief Executive Officer by facilitating efficient and effective flow of information between management and the board of directors. Further, the board believes the dual role of Chairman and Chief Executive Officer, in concert with the Lead Independent Director appointed by the board, serves the interests of stockholders by striking a balance between the development of corporate strategies and independent oversight of management. As discussed more fully below, we have appointed Mr. Finn as our Lead Independent Director.

The “Lead Independent Director” assists the board of directors in assuring effective corporate governance, and serves as chairman when the board of directors meets in independent director sessions. Our board of directors designated Mr. Finn to serve as Lead Independent Director. In this role, he may call and preside over executive sessions of the independent directors, without management present, as he deems necessary, serve as a liaison between the chair or the chief executive officer and the independent directors on certain matters, and has power to provide formal input on the agenda for meetings of the board. The Nominating and Corporate Governance Committee reviews this appointment annually and the full board has the opportunity to ratify the committee’s selection.

Our board of directors believes this structure is appropriate for our Company because our Chief Executive Officer has the best knowledge of the day-to-day operations of the Company and can make recommendations to the board based on his ongoing experience and “hands on” running of the Company. In addition, the Lead Independent Director, who is an independent member of our board, provides independent leadership within our board that strengthens its effectiveness and oversight of our business.

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Board’s Role in Risk Oversight

General

Risk is inherent with every business, and how well a business manages risk can ultimately determine its success. We face a number of risks, including general economic risks, credit risks, market risks, regulatory risks, strategic risks, cyber security risks, reputational risks and others, such as the impact of competition. Management is responsible for the day-to-day management of the risks we face, while the board, as a whole and through its committees, has responsibility for the oversight of risk management. In its risk oversight role, the board of directors has the responsibility to satisfy itself that the risk management processes designed and implemented by management are adequate and functioning as designed.

In 2015, we established our enterprise risk management program to assess, measure and monitor credit risk, market risk, liquidity and funding risk, capital adequacy, strategic risk, legal and compliance risk, reputation risk and operational risk. While the full board of directors is charged with ultimate oversight responsibility for risk management, various committees of the board and members of management also have responsibilities with respect to our risk oversight. In particular, the Risk Committee’s responsibilities include periodically reviewing and approving our enterprise risk management program and risk appetite framework; identifying emerging risks and ensuring there are plans to mitigate risks identified; reviewing stress testing activities surrounding credit, liquidity and capital, ensuring compliance with our risk appetite framework; and reviewing results of examinations by regulatory agencies and tracking remediation of reported findings. The board’s Compensation Committee monitors and assesses the various risks associated with compensation policies and individual incentive plans, and oversees incentives to ensure the level of risk-taking is consistent with our overall strategy.

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We believe that establishing the right “tone at the top” and providing for full and open communication between management and the board of directors are essential for effective risk management and oversight. Our executive management meets regularly with our other senior officers to discuss strategy and risks facing the Company. Senior officers contribute to enterprise risk reporting to the board and attend many of the board meetings, or, if not in attendance, are available to address any questions or concerns raised by the board on risk management-related and any other matters. Additionally, each of our board-level committees provides regular reports to the full board and apprises the board of our comprehensive risk profile and any areas of concern.

Cyber and Information Security

Our Information Technology Steering Committee (“ITSC”) is central to the board’s oversight of cybersecurity risks, which are incorporated into our overall risk management program overseen by our Risk Committee. The board provides oversight of technology-based risk management on significant technology risk exposures such as risks related to information security, fraud, data protection, business continuity, vendor management and cybersecurity. The Chief Technology Officer, Chief Risk Officer and Chief Information Security Officer regularly attend the committee meetings and provide comprehensive briefings and reporting no less than quarterly to ensure the highest levels of management are kept abreast of the cybersecurity posture and potential risks we face. As the Bank deploys new technology and platform innovations to gather, process, analyze, and provide information to execute transactions and meet the needs of its customers, the Bank ensures that its operations are effective on enhancing productivity to meet its strategic goals while mitigating technology risks through its efforts to improve cybersecurity, data privacy, and data management. Board and ITSC members receive reporting on significant cyber events including response efforts, legal obligations, and notification to regulators and/or customers when needed. The Risk Committee has approved a standalone Cybersecurity Risk Appetite Statement against which the Bank’s performance is measured quarterly.

While we look to numerous frameworks to ensure the Information Security Program is maintained in line with regulatory expectations and industry best practices, the National Institute of Standards and Technology (“NIST”) cybersecurity framework is the primary standard against which we benchmark ourselves. The program incorporates all of our security policies and covers the core elements of access control, infrastructure security, cybersecurity events and incident management, data protection, third-party vendor cyber risk oversight, payment security, and training and awareness. Independent assessment and benchmarking of the program are regularly completed. We continue to make significant investments in enhancing our cyber defense-in-depth capabilities and to strengthen our partnerships with the appropriate government and law enforcement agencies and other businesses in order to understand the full spectrum of cybersecurity risks in the operating environment, enhance defenses and improve resiliency against cybersecurity threats. We continually monitor our threat environment utilizing a robust asset management program, network security monitoring, regular patch management, threat intelligence, third party service oversight, and testing of key controls. We maintain a complex Business Continuity Plan and Incident Response Plan that is routinely updated and tested. Our staff receives formal information security training under a multifaceted approach that includes tabletop exercises, web-based training and regular phishing and social engineering training. We maintain a standalone cyber insurance policy that is intended to defray the costs of an information security breach. Our information security program is independently audited no less than annually and we perform routine internal and external penetration testing.

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Corporate Social Responsibility

We know that many of our stockholders expect that we conduct our business in a socially responsible manner through our actions and interactions with our customers, colleagues and within the communities that we serve. Since we were founded, we have worked to integrate corporate social responsibility into our activities. We strive to be a good corporate citizen by operating as an employer that is committed to our team members and, through our bank branches, by maintaining strong ties to the communities in which our customers live, work and do business. Although not an exhaustive list, examples of our activities that reflect our strong commitment to corporate social responsibility include:

Commitment to Community

Giving back to the communities we serve has always been an important part of our culture as a local community bank. We proudly support the communities in which we operate, not only through our banking operations, but through our employees’ volunteer and community-service efforts.

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Employee Engagement

We believe that our continued growth and future success will depend in large part on the quality of service provided by our employees. We understand that a highly engaged and empowered workforce is key to driving success for our customers, our business, our communities and our stockholders.

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We seek to provide a compelling value proposition to our employees by providing market-competitive pay and benefits which include retirement programs, broad-based bonuses, health and welfare benefits, paid time off, family leave and flexible work schedules.

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In 2025, we identified specific areas of focus in response to employee engagement survey results. Leadership, Feedback & Recognition, and Collaboration & Communication were the formal areas of focus. Leadership initiatives centered around increased visibility and frequency of communications resulting in live, recorded, and written messages from the Chief Executive Officer to staff, strategic senior leadership attendance at meetings and events, and leadership presence at semiannual milestone anniversary luncheons. For Feedback & Recognition, we leveraged Engagement Ambassadors to meet regularly and serve as a conduit for two-way communication and an accelerant for department engagement initiatives. For our Collaboration & Communication focus, we continued a successful partnership between O2 Cares and our CRA Officer to volunteer with Junior Achievement resulting in 80+ volunteers reaching more than 1,000 students in the Chicagoland area.

Sustainable Business Practices

We recognize the opportunity to advance economic and social impact through sustainable business operations. In our efforts to promote greater environmental responsibility and operate at an increased level of resource efficiency we:

Certain Relationships and Related Party Transactions

Statement of Policy Regarding Transactions with Related Persons

Transactions by us with related parties are subject to regulatory requirements and restrictions. These requirements and restrictions include Sections 23A and 23B of the Federal Reserve Act (which governs certain transactions by us with our affiliates) and the Federal Reserve’s Regulation O (which governs certain loans by us to our executive officers, directors and principal stockholders). We have also adopted policies to comply with these regulatory requirements and restrictions, including policies governing the approval of related party transactions. Our Audit Committee reviews and approves all related person transactions between the Company and related parties in accordance with NASDAQ’s rules and regulations. For purposes of this review, related person transactions are those transactions required to be disclosed under applicable SEC regulations.

Banking Relationships

Certain of our executive officers and directors have, from time to time, engaged in banking transactions with the Bank and are expected to continue such relationships in the future. All loans or other extensions of credit made by the Bank to such individuals were made in the ordinary course of business on substantially the same terms, including interest rates and collateral, as those prevailing at the time for comparable transactions with unaffiliated third parties and did not involve more than the normal risk of collectability or present other unfavorable features.

Compensation Committee Interlocks and Insider Participation

For the year ended December 31, 2025, our Compensation Committee consisted of Mr. McLean (Chair), Mr. Klaeser (Vice-Chair), Mr. Finn, Mr. Kotche, and Ms. York. No member of our Compensation Committee in 2025 was, during the last fiscal year, an officer or employee of the Company or formerly an officer of the Company. In addition, none has had any relationship with the Company of the type that is required to be disclosed under “Certain Relationships and Related Party Transactions.” During 2025, none of our executive officers served as a member of the board of directors, compensation committee or other board committee performing equivalent functions of another entity that had one or more executive officers serving as a member of the board of directors or Compensation Committee of the Company.

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Vote Standard for Bylaw Amendments

Our certificate of incorporation and bylaws authorize our board of directors to adopt, amend or repeal our bylaws by a majority vote. In addition, under Delaware law, our stockholders also have the power to adopt, amend or repeal our bylaws. Under our bylaws, such an action would require a majority of the shares having voting power present in person or represented by proxy at the meeting.

Stockholder Communications with Our Directors

Our stockholders may contact any member of the board of directors (including our Chairman or Lead Independent Director), or the board as a whole, through our Corporate Secretary, by mail at 37 South River Street, Aurora, Illinois 60507, or by e-mail at [email protected]. Any such communication should indicate whether the sender is an Old Second stockholder. Any communication will be forwarded promptly to the board as a group or to the attention of the specified director per your request. Communications that are personal grievances, commercial solicitations, customer complaints, incoherent, or obscene will not be communicated to our board or any director or committee of our board.

Stockholder Proposals and Director Nominations

Stockholder Nominations of Directors. Under our certificate of incorporation, a stockholder may nominate a candidate for election at a stockholder meeting by giving written notice, delivered to or mailed, to our Corporate Secretary, at 37 South River Street, Aurora, Illinois 60507, not fewer than 14 days nor more than 60 days before any meeting of the stockholders called for the election of directors. If notice of the meeting is given to stockholders less than 21 days before the date of the meeting, such written nomination must be delivered or mailed, as prescribed, to our Corporate Secretary, not later than the close of business on the seventh day following the day on which notice of the meeting was mailed to stockholders. Each written nomination must set forth (a) the name, age, business address and, if known, residence address of each nominee proposed in such written nomination; (b) the principal occupation or employment of each such nominee for the past five years; and (c) the number of shares of our stock beneficially owned by each such nominee and by the nominating stockholder.

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Stockholder Proposal at the Meeting. A stockholder seeking to present any business at an annual meeting must submit a notice in writing to our Corporate Secretary, at 37 South River Street, Aurora, Illinois 60507, not earlier than 120 days and not later than 90 days prior to the first anniversary of the preceding year’s annual meeting. If the date of the annual meeting is moved to more than 30 days before or more than 60 days after the anniversary date of the previous year’s meeting, for notice by the stockholder to be timely it must be delivered to us not earlier than 120 days prior to the date of such annual meeting and not later than 90 days prior to the date of such annual meeting or, if the first public announcement of the date of such annual meeting is less than 100 days prior to the date of such annual meeting, then the tenth day following the day on which public announcement of the date of such meeting is first made by the Company. Our bylaws require the stockholder’s notice to the Company with respect to a stockholder proposal (other than a director nomination) for an annual meeting of stockholders, to include, among other things, (a) the stockholder’s name and address; (b) information about the stockholder’s stock ownership in the Company and certain interests and relationships; and (c) a description of the business the stockholder desires to bring before the meeting.

Proposals in Our Proxy Statement. Under SEC rules, for a stockholder’s proposal to be included in our proxy statement and proxy card for the 2027 Annual Meeting of Stockholders, you must file a written notice of the proposal with our Corporate Secretary, at 37 South River Street, Aurora, Illinois 60507, not less than 120 calendar days before the date of our proxy statement released to stockholders in connection with the previous year’s annual meeting, or December 7, 2026, and must otherwise comply with the rules and regulations set forth by the SEC. However, if the date of next year’s annual meeting is changed by more than 30 days from the date of this year’s meeting, then the deadline is a reasonable time before we begin to print and send our proxy materials.

Additional Requirements for Director Nominations Under SEC Rules. In addition to satisfying the requirements described above under our certificate of incorporation and bylaws, stockholders who intend to solicit proxies in support of director nominees other than the Company’s nominees must comply with the additional requirements of Rule 14a-19 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). In particular, a stockholder intending to solicit proxies in support of director nominees other than the Company’s nominees must provide notice to the Company that sets forth the information required by Rule 14a-19 and must comply with the timing and other requirements specified in that rule. Such notice must be provided to the Company no later than 60 calendar days prior to the anniversary of the date of the previous year’s annual meeting of stockholders. If the date of the annual meeting is changed by more than 30 days from the anniversary of the previous year’s annual meeting, the notice must be provided by the later of (i) 60 calendar days prior to the date of the annual meeting or (ii) the tenth day following the day on which the Company first publicly announces the date of the annual meeting.

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SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS

AND MANAGEMENT

The following table sets forth certain information with respect to the beneficial ownership of our common stock as of March 20, 2026, by each director and nominee for director, by each named executive officer, by all of our executive officers, directors and director nominees as a group, and each person known by us to be the beneficial owner of more than 5% of our outstanding common stock.

Unless otherwise noted below, the address of each beneficial owner listed in the table is c/o Old Second Bancorp, Inc., 37 South River Street, Aurora, Illinois 60507. Except as indicated by the footnotes below, we believe, based on the information furnished to us, that the persons and entities named in the tables below have sole voting and investment power with respect to all shares of our common stock that they beneficially own, subject to applicable community property laws. We have based our calculation of the percentage of beneficial ownership on 51,779,472 shares of common stock outstanding as of March 20, 2026. Beneficial ownership has been determined for this purpose in accordance with Rule 13d-3 under the Exchange Act, under which a person is deemed to be the beneficial owner of securities if he or she has or shares voting power or investment power with respect to such securities or has the right to acquire beneficial ownership of securities within 60 days of March 20, 2026.

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DELINQUENT SECTION 16(a) REPORTS

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Section 16(a) of the Exchange Act requires our directors, executive officers and beneficial owners of more than 10% of common stock to file with the SEC reports regarding their ownership and changes in ownership of our securities. To our knowledge, these insiders complied with all Section 16(a) filing requirements during 2025, except a late Form 4 report for Mr. Campbell which was filed on October 30, 2025.

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COMPENSATION DISCUSSION AND ANALYSIS

This Compensation Discussion and Analysis (“CD&A”) is intended to assist our stockholders in understanding our compensation programs, the philosophy underlying our compensation strategy and the fundamental elements of the compensation paid to our “named executive officers” whose 2025 compensation information is provided in the tables following this discussion. Our named executive officers as of December 31, 2025, are noted in the following table, along with their current titles:

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Introduction

Our CD&A is organized as follows:

Overview and Executive Summary

Business Overview. We provide lending, deposit, and trust services for businesses and individuals. We offer competitive commercial and personal banking products and are committed to providing superior customer service. We place a high priority on community service and are actively involved with many civic and community projects in the communities where we conduct our business. We operate in an intensely competitive and uncertain business environment. From a business perspective, not only do we compete with numerous companies in our markets for customers, but we also compete with many different types and sizes of organizations for senior leadership capable of executing our business strategies. Among other challenges, our business model requires experienced leaders with banking and operational expertise who are capable of taking on high levels of personal responsibility in an ever-evolving banking industry and economy.

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Financial and Operational Performance. During 2025, we continued our emphasis on sustaining profitability and growth. Some accomplishments in 2025 included:

Overview of Certain Compensation-Related Performance Metrics. In 2025, our Compensation Committee selected, among others, corporate performance metrics for our annual incentive plan based on our:

Our Compensation Committee uses these adjusted measures because it believes they provide a useful supplemental view of our core operating performance for executive compensation purposes by excluding items that are not viewed as indicative of our ongoing operating performance or that could otherwise reduce comparability from period to period. Our Compensation Committee does not use these adjusted measures as a substitute for GAAP results, but rather as additional performance measures to evaluate results in a manner it believes better aligns compensation outcomes with our operating performance.

Overview of Our Executive Compensation Programs. The Company and the Bank share an executive management team. The compensation packages of our named executive officers are determined and approved by our Compensation Committee based on their performance and roles for both the Company and the Bank.

We are committed to paying for performance. This commitment is reflected by the significant portion of our named executive officers’ compensation that is provided through performance-based programs. Our executive compensation programs evolve and are adjusted over time to support our business goals and to promote both near- and long-term profitable growth. Total compensation for each named executive officer varies with performance in achieving financial and non-financial objectives.

Accordingly, our executive compensation, particularly metrics for our short-term incentive plans, focused on the following goals and accountabilities: our net income growth, asset quality, expense control and efficiency of operations, and department and individual performance. These metrics were prudently designed to contain and minimize risk while at the same time emphasizing growth and profitability.

Say-on-Pay. At our 2025 annual meeting of stockholders, approximately 94% of the votes cast on the advisory say-on-pay proposal were voted in favor of the compensation of our named executive officers. Our Compensation Committee considered the outcome of that vote as part of its annual review of our executive compensation program and concluded that our overall executive compensation philosophy and program structure remained appropriate and continued to support our compensation objectives. In reaching that conclusion, our Compensation Committee considered the say-on-pay outcome together with our performance, competitive market data and its ongoing assessment of the design and effectiveness of our executive compensation program.

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Clawback Policy. The Compensation Committee believes it is appropriate to adjust or recover incentive awards or payments in the event the financial reporting measures upon which they are based are restated or otherwise adjusted in a manner that would reduce the size of an award or payment. As required under SEC and NASDAQ rules, the board of directors approved the Incentive Compensation Recovery Policy effective August 15, 2023. The policy generally requires recovery of any erroneously awarded incentive-based compensation (calculated based on the error that was subsequently corrected in an accounting restatement), regardless of any misconduct or knowledge of the officer who received the compensation. But recovery is generally not required if the compensation was received before the person began serving as an officer, or the person did not serve as an officer at any time during clawback period. A clawback will be triggered by both a “Big R” restatement — one that corrects an error in previously issued financial statements that is material to the previously issued financial statement and requires a Form 8-K filing — as well as a “Little r” restatement — one that corrects an error that would result in a material misstatement if the error was corrected in the current period or left uncorrected in the current period and generally does not require filing a Form 8-K. Our clawback policy also provides our board of directors discretion to clawback any incentive compensation paid to an officer if the board determines it is just, practical, equitable, and in the best interests of the Company to do so, regardless of whether the Company is required to prepare a “Big R” restatement or “Little r” restatement.

Objectives of Our Compensation Program

The goal of our compensation program is to align the interests of management with those of our stockholders while minimizing undue risk-taking. The Compensation Committee has designed our executive compensation program in a manner that does not provide our executives with incentives to engage in business activities or other behavior that would threaten our value or the investments of our stockholders.

The executive compensation program is intended to accomplish the following objectives:

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Below we summarize certain governance practices we have implemented to drive performance and those we have not implemented because we do not believe they would serve our stockholders’ long-term interests.

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Elements of Compensation

Our Compensation Committee structures our executive compensation program to balance fixed and variable compensation, short-term and long-term incentives, and cash and equity compensation. In doing so, our Compensation Committee believes base salary provides a fixed level of compensation for the scope of an executive’s role and responsibilities, annual cash incentives reward annual company and individual performance, and long-term equity awards align the interests of our executives with long-term stockholder value creation while also supporting retention.

Our named executive officers’ compensation program consists of four main components: (a) base salary, (b) annual cash incentives, (c) equity awards and (d) additional benefits.

The Compensation Committee’s decisions regarding each of the components for the named executive officers are based in part on the Compensation Committee’s subjective judgment and consider qualitative and quantitative factors, as discussed below. In reviewing an executive officer’s compensation, the Compensation Committee considers and evaluates all components of the officer’s total compensation package. This involves reviewing base salary, cash incentives, equity incentive awards, perquisites, participation in our non-qualified executive plans, participation in our 401(k) plan and any other payments, awards or benefits that an officer earns. Additionally, the Compensation Committee takes into consideration any amount an executive officer is entitled to upon retirement, termination or a change-in-control event.

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The following overview explains the structure and rationale of the elements of compensation used for 2025.

Base Salary. The Compensation Committee believes that base compensation should offer security to each executive sufficient to maintain a stable management team and environment. In establishing an executive officer’s initial base salary the Compensation Committee considers, among other things, the executive’s level of responsibility, prior experience, breadth of knowledge, the competitive salary practices at peer companies, internal performance objectives, education, internal pay equity, potential bonus and equity awards, level of benefits and perquisites and the tax deductibility of base salary.

The Compensation Committee reviews salaries of the named executive officers on an annual basis. As with all of its decisions regarding compensation levels, when reviewing salaries the Compensation Committee considers the levels of all aspects and components of the officer’s compensation, including the individual’s potential bonus and equity awards as well as the level of benefits and perquisites offered. All of these factors are considered on a subjective basis in the aggregate, and none of the factors is accorded a specific weight.

Annual Cash Incentives. The Compensation Committee believes that annual cash incentive compensation is an integral component of our total compensation program that links executive decision-making and performance with our annual strategic objectives. We use this component to focus management on the achievement of corporate financial goals while considering the mitigation of any risks which may affect our overall financial performance.

In February 2025, the Compensation Committee established performance metrics under the Old Second Bancorp, Inc. Executive Annual Incentive Plan, which we refer to as our “Incentive Plan.” Under the Incentive Plan, as soon as practicable at the beginning of each fiscal year, the Compensation Committee, in consultation with our Chief Executive Officer, selects key performance objectives, which will be used to determine the actual incentive cash payment to be awarded to our executive officers upon the achievement of the selected performance objectives. Generally speaking, performance targets are set so that improvement in a performance objective is necessary in order to receive any or all of the incentive award with respect to that objective. In addition, under the Incentive Plan, in order to be eligible for a cash incentive payment with respect to a particular year, the executive must also meet the expectations of his position during such year.

Maximum incentive opportunities are capped under the Incentive Plan to avoid encouraging excessive risk-taking and to avoid any focus on maximizing short-term results at the expense of our long-term soundness.

Equity Awards. The Compensation Committee believes that senior management equity ownership effectively aligns the interests of senior management with those of our stockholders. Accordingly, we have implemented equity-based incentives to both encourage our management’s long-term service and give management a more direct interest in our future success. The equity incentive plan in effect in 2025, which was originally approved by our stockholders at our 2019 annual meeting of stockholders, and amended and restated for the second time by our stockholders at our 2025 annual meeting of stockholders to increase the number of authorized shares of common stock under the 2019 Equity Incentive Plan to a total of 2,600,000 shares (the “Equity Incentive Plan”), authorizes the granting of qualified stock options, non-qualified stock options, restricted stock, restricted stock units and stock appreciation rights.

All awards are at the discretion of the Compensation Committee and are generally subjective in nature. In determining the number of equity awards to be granted to executive officers, the Compensation Committee considers individual and corporate performance goals and achievement as measured by those goals, the executive’s position and his or her ability to affect profits and stockholder value, as well as the level of awards granted to individuals with similar positions at our peer organizations. Because of the nature of equity awards, the Compensation Committee also evaluates prior awards of stock options and restricted stock and considers the overall wealth accumulation of a given executive officer through such awards.

As discussed below in “Analysis of 2025 Compensation—Long-Term Equity Compensation,” in 2025, the Compensation Committee granted our named executive officers service-based restricted stock units that are subject to three-year cliff vesting. In addition, in 2025, the Compensation Committee awarded performance-based restricted stock units to each of the named executive officers subject to specified performance conditions to be measured over the three-year period ending December 31, 2027.

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Additional Benefits

Retirement Benefits. We sponsor a tax-qualified 401(k) savings plan and trust intended to be qualified under Section 401(k) of the Internal Revenue Code. Virtually all employees are eligible to participate after meeting certain age and service requirements. Eligible employees are permitted to contribute up to a dollar limit set by law. Participants can choose between several different investment options under the 401(k) plan, including shares of our common stock.

During 2025, we provided a matching contribution on elective deferrals to eligible participants in an amount equal to 100% of the first 3% of each participant’s contributions, and 50% of the next 2% of the participant’s contributions. There is also a profit-sharing portion of the 401(k) plan which provides for an annual discretionary contribution to the retirement account of each employee based in part on our profitability in a given year and on each participant’s annual compensation. The contribution amount granted each year is on a discretionary basis and there is no set formula used by the Compensation Committee. For 2025, the Compensation Committee elected not to make a discretionary profit-sharing contribution.

Deferred Compensation. On September 23, 2020, the Board of Directors adopted the Old Second Bancorp, Inc. Voluntary Deferred Compensation Plan (the “Restated Deferred Compensation Plan”), which amended and restated our prior Executive Deferred Compensation Plan. The Restated Deferred Compensation Plan became effective on January 1, 2021 and, among other things, removed the mandatory company matching contributions for 2021 and beyond. However, the Compensation Committee may, in its discretion, make supplemental contributions (“Company Contributions”) to a participant’s retirement distribution account in the form of (a) matching contributions on behalf of participants who elect to make the maximum permissible deferral amount under the applicable 401(k) Plan, including catch-up contributions, and (b) profit sharing contributions. Company Contributions vest according to the schedule specified by the Compensation Committee on or before the time such contributions are made.

Under the Restated Deferred Compensation Plan, participants are permitted to make hypothetical investments with respect to their account balances. The participants may select such hypothetical investments from an array of publicly-traded mutual funds that are held in an insurance company separate account. Participants may elect to receive their deferred compensation balance in a lump sum or in installments. Participants may make a withdrawal from the plan during their employment in the event of hardship as approved by the plan’s administrator. The plan is administered through an independent service provider. Messrs. Eccher, Collins, Adams, and Pilmer currently have account balances under our deferred compensation plan.

Perquisites and Other Benefits. We provide general and customary benefit programs to executive officers and other employees. Benefits offered to executives are intended to serve a different purpose than base salary, bonus, cash incentive and equity incentive awards. While the benefits offered are competitive with the marketplace and help attract and retain executives, the benefits also provide financial security for employees for retirement as well as in the event of illness, disability or death. The benefits we offer to executive officers are generally those offered to other employees with some variation to promote tax efficiency and replacement of benefit opportunities lost to regulatory limits, although there are some additional perquisites that may only be offered to executive officers. Because of the nature of the benefits offered, the Compensation Committee normally does not adjust the level of benefits offered on a year-to-year basis. We will continue to offer benefits, the amount of which shall be determined from time-to-time in the sole discretion of the Compensation Committee.

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The following table summarizes the benefits and perquisites we do and do not provide as well as identifies those employees that may be eligible to receive them:

It is our belief that perquisites for executive officers should be very limited in scope and value. Due to this philosophy, we have generally provided very nominal benefits to executives that are not available to full-time employees, and we plan to continue this approach in the future. We do provide country club memberships to certain executives and managers in the ordinary course of business to give them the opportunity to bring in and recruit new business opportunities. These individuals are eligible to use the club membership for their own personal use. Additionally, we provide Messrs. Eccher, Adams, Collins, Campbell, and Pilmer with an automobile allowance to enable them to visit our banking locations on a regular basis as well as to call on our customers. We have disclosed the value of all perquisites to named executive officers in the Summary Compensation Table even if they fall below the disclosure thresholds under the SEC rules. We will continue to offer perquisites, the amount of which shall be determined from time-to-time in the sole discretion of the Compensation Committee.

Severance and Change in Control Arrangements

Employment Agreements and Compensation and Benefits Assurance Agreements. Under his employment agreement, we provide Mr. Eccher with certain “double trigger” severance benefits in the event of his involuntary termination following a change in control, as well as salary continuation following certain other involuntary terminations. We have also entered into Compensation and Benefits Assurance Agreements with each of our other named executive officers which also provide “double trigger” severance benefits in the event of a qualifying termination following a change in control. We believe these agreements help us recruit and retain executives with the experience, skills, knowledge and background needed to achieve our business goals and strategy. For a detailed description of the severance and change in control benefits applicable to our named executive officers, see the discussion below under “Potential Payments Upon Termination or Change in Control.”

Acceleration of Equity Awards. All employees, including our named executive officers, who receive equity awards under our Equity Incentive Plan will immediately vest in any unvested equity awards held by such employees upon the occurrence of a change in control if (a) the equity plan and the respective awards are not assumed by the surviving entity or (b) the plan and the respective awards are assumed by the surviving entity but the individual is terminated without cause or resigns for good reason. Additionally, under the terms of the Employment Agreement and Assurance Agreements noted above and described in greater detail below, all equity awards held by a named executive officer will become vested and exercisable upon a qualifying termination following a change in control.

No Tax Gross-Ups. We do not provide excise tax gross-ups on benefits under any change in control provisions or other agreements with named executive officers. All of our named executive officers currently have employment agreements or Compensation and Benefits Assurance Agreements that provide that in the event the officer would be subject to excise tax for any amounts payable under such agreement, the amounts to be paid will be reduced to such lesser extent that would result in no portion of such amounts being subject to excise taxes.

Compensation Process

The Compensation Committee has overall responsibility for evaluating the compensation plans, policies and programs relating to our executive officers. Further, as required by guidance issued by the Federal Reserve and other financial institution regulatory agencies, and the SEC’s guidance regarding risk associated with compensation arrangements (each as described more fully below), the Compensation Committee is also responsible for a more expansive risk review with respect to the compensation plans, policies and programs maintained for our employees.

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During 2025, the Compensation Committee convened in February, May, August and December. Mr. McLean, as Chair of the Compensation Committee, also met, as needed, with internal staff members to compile compensation information for this proxy statement. The Compensation Committee also met in February 2026 to approve salaries, incentive plans and performance metrics for 2026, as well as approving officer incentives earned during 2025.

Role of Compensation Consultant. The Compensation Committee’s charter gives it the authority to delegate its responsibility to members or subcommittees of the Compensation Committee. Also, the charter gives the Compensation Committee the authority to hire outside consultants to further its objectives and responsibilities. The Compensation Committee retained AON/McLagan in 2025 to provide services in connection with a review and analysis of compensation paid to our named executive officers and board of directors. In keeping with the Compensation Committee’s philosophy of comparing our compensation with that of the competitive marketplace on an annual basis, AON/McLagan also provided the Compensation Committee an updated market analysis of our executive compensation program.

Role of Executive Officers. The Compensation Committee relies upon the input of management when carrying out its responsibilities in establishing executive compensation. The Compensation Committee relies on Mr. Eccher’s input in establishing compensation for our named executive officers other than himself. Management provides the Compensation Committee with evaluations as to employee performance, guidance on establishing performance targets and objectives and recommends salary levels and equity awards. The Compensation Committee also consults with management on matters that are relevant to executive compensation and benefit plans where board or stockholder action is expected, including the adoption of new plans or the amendment of existing plans. Finally, the Compensation Committee consults with our management, specifically the Bank’s Chief Risk Officer, in completing the risk review with respect to employee compensation plans. Our Compensation Committee reviews management’s recommendations, together with information provided by its independent compensation consultant and other relevant factors, and makes the final compensation decisions for our executive officers. No executive officer participates in any recommendation, discussion or decision regarding his or her own compensation.

Peer Group. Market pay practices are one of many factors we consider in setting executive pay levels and designing compensation programs. Information on pay levels and practices is gathered from a group of publicly traded companies selected based on their business focus, scope and location of operations, size and other considerations. Our peer group of 21 financial institutions was jointly presented by AON/McLagan and management and approved by the Compensation Committee. The group is periodically reviewed, with changes made to reflect merger and acquisition activity, financial situation and development, and other considerations. The institutions included in the peer group for 2025 include:

Analysis of 2025 Compensation

This section describes the decisions made by the Compensation Committee with respect to the compensation for our named executive officers for 2025.

Base Salary. We annually review the base salaries of the named executive officers to determine whether or not they will be adjusted, as described above. The salaries for 2025, determined by the Compensation Committee at the beginning of 2025, are set forth in the Summary Compensation Table below. In determining base salary levels, we generally considered the following:

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The following table details the base salary of our named executive officers for the periods presented.

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N/M – Not Meaningful

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For 2025, the Compensation Committee increased the base salaries of all listed executives (except Darin Campbell) to reflect both overall corporate performance in 2024—including net income growth—and each officer’s individual contributions. In Mr. Campbell’s case, his base salary was determined in his employment agreement at the time of the closing of the Bancorp Financial, Inc. acquisition on July 1, 2025.

Annual Cash Incentive Payments. As discussed above, under our Incentive Plan, the Compensation Committee, in consultation with our Chief Executive Officer, selects key performance objectives, which will be used to determine the actual incentive cash payment to be awarded to our executive officers upon the achievement of the selected performance objectives. In addition, under the Incentive Plan, the Compensation Committee also determines each executive officer’s target incentive opportunity, expressed as a percentage of base salary.

For 2025, the Compensation Committee set the target potential incentive payment, expressed as a percentage of base salary, as follows:

For 2025, the Compensation Committee selected four performance objectives, as identified in the following table (and described in more detail below), and assigned a weight for each performance objective, stated as a percentage of the total target incentive payment.

The performance objectives chosen by the Compensation Committee and the assigned weight for each objective for 2025 performance were as follows:

The Compensation Committee established threshold, target and maximum performance levels and weights for each selected corporate goal. Threshold represents the minimum level of performance at which, if achieved, a payment is earned on each corporate goal. If performance is below the threshold level for any particular corporate goal, no payment will be earned; however, payment will be earned for other corporate objectives that are achieved if at least at a threshold level of performance. Maximum represents the maximum level of performance at which, if achieved, a maximum payment is earned on each corporate goal. If performance exceeds the maximum level for any corporate goal, no further incentive above the maximum incentive for such corporate goal is earned. Actual performance between threshold, target and maximum performance levels will be interpolated to determine the amount of payment based on relative achievement of the corporate objectives.

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How we defined each of these corporate objects is set forth below.

Adjusted Net Income Growth

Each named executive officer had a portion of their annual incentive tied to this performance objective in 2025. The Compensation Committee believes that our growth, as measured by our Adjusted Net Income, is an appropriate performance measure because it focuses on our financial performance, which in turn affects stockholder value. See page 49 for the reconciliation of this non-GAAP measure to GAAP Net Income. In addition, the Compensation Committee determined to use a return on average assets (“ROAA”) metric for our performance, defined as net income divided by average assets, as compared to our peer group. The ROAA metric superseded the Adjusted Net Income performance metric if we performed as well as, or better than, the median ROAA of our peer group.

The Compensation Committee applied the following scale to determine how much of the total assigned weight for this performance objective each named executive officer could receive based on our net income:

Our Adjusted Net Income in 2025 was $102.6 million, and our reported net income was $80.3 million. Our adjusted ROAA of 1.62%, which fell between the 75% and 90% peer group medians. Accordingly, each named executive officer earned 128.9% of the assigned weight for this performance objective.

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Asset/Credit Quality

Mr. Eccher, Mr. Collins and Mr. Pilmer each had a performance objective related to asset quality, which was composed of two metrics, each making up 50% of the total assigned weight for this performance objective. The Compensation Committee believes that a continued focus by these executives on our asset/credit quality will ensure that we are working toward sustainable growth and profitability.

These metrics were (a) nonperforming assets to total loans plus OREO and repossessed assets, and (b) net chargeoffs to average total loans. As noted in the table below, each of these asset/credit quality metrics represents 50% of this total performance metric, if earned at target.

At December 31, 2025, our nonperforming assets to total loans plus OREO and repossessed assets ratio was 1.06%, which resulted in 120% earnings from this performance metric. In addition, our net chargeoffs to average loans ratio was 0.21%, excluding the National Specialty Lending loans, while the peer group median net chargeoffs to average loans ratio for 2025 was 0.18%. This resulted in 77.30% earnings from this performance metric.

Adjusted Efficiency Ratio

The Compensation Committee believes that expense control and efficiency of operations is a goal we should continually strive for in order to provide for the best financial return for our stockholders. Further, the Compensation Committee believes that our named executive officers are best situated to impact our efforts in this regard. As such, Mr. Eccher and Mr. Adams each had a portion of their annual incentive tied to our Adjusted Efficiency Ratio, as noted in the following table. For 2025, our Adjusted Efficiency Ratio was calculated as noninterest expense, excluding net OREO expenses, amortization of core deposits, acquisition related costs, and net gains on branch sales, divided by the sum of net interest income, on a fully tax equivalent basis, and total noninterest income, less net gains or losses on security sales, net losses on mortgage servicing rights, death benefits realized on BOLI, and including a tax equivalent adjustment on the increase in the cash surrender value of BOLI.

For 2025, our Adjusted Efficiency Ratio at year-end was 53.15% and, therefore, Mr. Eccher and Mr. Adams each earned 110% of their applicable assigned weight for this performance metric.

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Department and Individual Performance

The Compensation Committee also set performance metrics for Mr. Eccher, Mr. Adams, Mr. Collins, Mr. Campbell, and Mr. Pilmer related to their respective departments and/or individual performance to promote the leadership and development of our various lines of business. For 2025, Mr. Eccher was evaluated on the executive team’s performance as well as improvements related to employee survey results, and earned 5% of base salary on a target of 5%. Mr. Adams was evaluated on finance, information technology, loan and deposit operations and accounting department strategies and efficiencies, and earned 5% of base salary on a target 5%. Mr. Collins was evaluated on residential lending performance and overall asset quality, and earned 10% of base salary on a target of 10% for this performance metric. Mr. Campbell was evaluated on the successful integration of Evergreen Bank teams from the acquisition as well as improvements to contribution margin, and earned 72% of base salary on a target of 50% for this performance metric. Mr. Pilmer was evaluated on the growth of our commercial lending performance, commercial deposits and commercial fee income, and earned 13.0% of base salary on a target 10% for this performance metric.

Total 2025 Annual Cash Incentive Plan Awards

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As outlined above, the Compensation Committee reviewed our performance and the performance of each department and executive officer, as applicable. Based on this review, the Compensation Committee approved awards at an amount equal to an interpolated amount between the total potential threshold incentive and the total maximum incentive for each performance objective (if the threshold performance level was obtained for such objective). In determining final annual cash incentive payouts for 2025, our Compensation Committee retained and exercised limited discretion to account for individual performance and other qualitative considerations described above. Our named executive officers’ actual cash incentive awards for 2025 are noted in the table below, along with the percentage of the total target incentive each officer achieved.

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For 2025, each named executive officer’s target annual cash incentive opportunity was established as a percentage of base salary. The company performance component of each award was determined based on our achievement against the applicable pre-established performance measures described above, including adjusted net income and adjusted efficiency ratio, and the resulting payout level for that component was calculated in accordance with the applicable performance scale. Our Compensation Committee also considered individual performance, including leadership, strategic execution, risk management, operational performance and other qualitative factors, in determining the final annual cash incentive opportunity for each named executive officer, to the extent applicable under our program design.

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Long-Term Equity Compensation.

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Our Compensation Committee structures our executive compensation program to balance fixed and variable compensation, short-term and long-term incentives, and cash and equity compensation. In doing so, our Compensation Committee believes base salary provides a fixed level of compensation for the scope of an executive’s role and responsibilities, annual cash incentives reward annual company and individual performance, and long-term equity awards align the interests of our executives with long-term stockholder value creation while also supporting retention.

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2025 TRSU Awards. In 2025, the Compensation Committee approved equity grants for our named executive officers comprised of time-vesting restricted stock units, or TRSUs, as shown in the following table.

The TRSUs are subject to three-year cliff vesting, with accelerated vesting in certain circumstances as described in the “Potential Payments upon Termination or Change in Control” section below.

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2025 PRSU Awards. In 2025, the Compensation Committee also approved an award of performance-based restricted stock units, or PRSUs, to our named executive officers, as shown in the following table.

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The performance period for these awards began on January 1, 2025, and ends on December 31, 2027. The PRSUs will vest contingent upon the satisfactory achievement of the selected performance metrics, each measured relative to a peer group of 125 banks. The performance metrics selected by the Compensation Committee for the above-referenced awards are:

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The number of PRSUs that ultimately vest and convert to shares may range from 0% to 175% of the underlying PRSUs originally awarded, depending on our performance relative to these performance metrics.

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Results of 2023 PRSU Awards. The final performance period for our 2023 PRSUs ended on December 31, 2025. While each performance metric was measured annually, the awards were also subject to a service requirement through the date we issued our 2025 audited financial statements. The PRSUs had a payout range from 0% of target for below threshold performance, 25% of target for threshold performance, 100% of target for target performance and 175% of target for maximum performance. The performance metrics, weight and relative goals are disclosed in the table below, along with the percentage of target achieved, as measured over the three-year period.

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Based on the above, the 2023 PRSUs were earned at 175% of target for relative return on average tangible common equity and 175% of target for growth in relative book value per share. Payment of the earned portion of the 2023 PRSUs occurred on March 2, 2026, the date the Compensation Committee certified the performance results, and were as follows:

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Perquisites and Other Benefits. While the Compensation Committee reviews and monitors the level of other compensation offered to the named executive officers, the Compensation Committee typically does not adjust the level of benefits offered on an annual basis. The Compensation Committee does consider the benefits and perquisites offered to the named executive officers in its evaluation of the total compensation received by each. The perquisites received by the named executive officers in 2025 are reported in the Summary Compensation Table below. The benefits offered in 2025 to the named executive officers are expected to continue for 2026.

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Regulatory Considerations

As a publicly-traded financial institution, we must contend with several often-overlapping layers of regulations when considering and implementing compensation-related decisions. These regulations do not set specific parameters within which compensation decisions must be made, but do require the Compensation Committee to be mindful of the risks that often go hand-in-hand with compensation programs designed to incentivize the achievement of better than average performance. While the regulatory focus on risk assessment has been heightened over the last several years, the incorporation of general concepts of risk assessment into compensation decisions is not a recent development.

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The Compensation Committee continues to believe in and practice a sensible approach to balancing risk-taking and rewarding reasonable, but not necessarily easily attainable, goals and this has always been a component of its overall assessment of the compensation plans, programs and arrangements it has put in place for our named executive officers. The Compensation Committee believes we have adequate policies and procedures in place to balance and control any risk-taking that may be incentivized by the employee compensation plans. The Compensation Committee further believes that such policies and procedures will work to limit the risk that any employee would manipulate reporting earnings in an effort to enhance his or her compensation.

In making decisions about executive compensation, in addition to the above, we also consider the impact of other regulatory provisions, including: the provisions of the Internal Revenue Code of 1986, as amended (the “Code”), such as Code Section 162(m) that may limit the tax deductibility of certain compensation; Code Section 409A regarding nonqualified deferred compensation; and Code Section 280G regarding excise taxes and deduction limitations on golden parachute payments made in connection with a change in control. In making decisions about executive compensation, we also consider how various elements of compensation will impact our financial results. For example, we consider the impact of FASB ASC Topic 718, which requires us to recognize the compensation cost of grants of equity awards based upon the grant date fair value of those awards.

Code Section 162(m) generally prohibits a federal income tax deduction to public companies for compensation over $1,000,000 paid to a “covered employee.” A “covered employee” includes (a) the Chief Executive Officer, (b) the Chief Financial Officer, (c) the three other most highly compensated executive officers, and (d) any individual who was a covered employee for any taxable year beginning after December 31, 2016. Before 2018, we were permitted to receive a federal income tax deduction for qualifying “performance-based” compensation as defined under Code Section 162(m) without regard to this $1,000,000 limitation. However, updated U.S. tax legislation eliminated the performance-based exception. These new rules became effective starting in 2018 for us. To the extent that in 2018 or any later year, the aggregate amount of any covered employee’s salary, bonus, and amount realized from vesting of restricted stock units or other equity awards, and certain other compensation amounts that are recognized as income for federal income tax purposes by the covered employee exceeds $1,000,000 in any year, we will not be entitled to a U.S. federal income tax deduction for the amount over $1,000,000 in that year. The Compensation Committee has not adopted a formal policy regarding tax deductibility of compensation paid to our executive officers, and may determine it is appropriate to provide compensation that may exceed deductibility limits in order to recognize performance, meet market demands, retain key executives, and take into account other appropriate considerations.

Compensation-Related Governance Policies

Common Stock Ownership and Retention Guidelines for Our Chief Executive Officer

In order to align the interests of our chief executive officer with our stockholders, we have adopted a policy that requires our chief executive officer to develop a significant equity stake in the Company. The Compensation Committee is responsible for monitoring compliance with these stock ownership and retention guidelines.

Under the policy our chief executive officer must acquire and hold shares of our common stock equal in value to at least three times his or her annual base salary. The officer will have five years from the date he or she first becomes subject to these guidelines to achieve these target ownership levels. If the officer acquires share of common stock under our equity-based incentive plans he or she must hold at least 50% of all net after-tax acquired shares until these stock ownership guidelines are satisfied. The following share types are included under these guidelines: shares directly owned, family-owned shares, retirement plan shares and unvested time-based restricted stock. Stock options that are unexercised, regardless of their vesting status and in-the-money value, are not counted toward satisfaction of these guidelines. Unvested performance-based restricted stock is also not counted toward stock ownership. Currently, our chief executive officer is in compliance with these guidelines.

Prohibitions on Hedging and Pledging

We consider it improper and inappropriate for our directors, officers and employees to engage in short-term or speculative transactions in our securities or in other transactions in our securities that may lead to inadvertent violations of the insider trading laws. Accordingly, under our Insider Trading Policy, we prohibit:

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COMPENSATION COMMITTEE REPORT

The Compensation Committee has reviewed and discussed the foregoing CD&A with management. Based on the Compensation Committee’s review and discussion with management, the Compensation Committee has recommended to our board of directors that the CD&A be included in this proxy statement and in Old Second’s Annual Report on Form 10-K for the year ended December 31, 2025.

Submitted by:

Mr. Hugh McLean, Chair

Mr. Barry Finn

Mr. Dennis Klaeser

Mr. Keith Kotche

Ms. Jill York

Members of the Compensation Committee

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EXECUTIVE COMPENSATION

Summary Compensation Table

The following table sets forth information concerning the compensation of our named executive officers: