Bank of Marin Bancorp

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. )

Payment of Filing Fee (Check the appropriate box):

Proxy

Statement

Wednesday, May 21, 2025

Bank of Marin Corporate Headquarters

504 Redwood Boulevard, Suite 100

Novato, California

Dear Fellow Shareholders,

During 2024, Bank of Marin was able to successfully navigate the challenging operating environment created by the economic uncertainty and interest rate movements. Given the strength of our balance sheet and high levels of capital and liquidity, we were able to execute on a balance sheet repositioning strategy that resulted in a higher net interest margin and level of profitability in the second half of the year. Furthermore, we believe we are well positioned to capitalize on any improvement we see in economic conditions and future loan demand.

At the same time, we continued to tightly manage expenses including taking actions that reduced operating expenses, while continuing to make prudent investments in banking talent and technology. The talent we have added to our banking team has resulted in a higher level of loan production that meets our disciplined underwriting and pricing criteria, which we believe will continue in 2025.

The positive trends we are seeing in our net interest margin combined with our prudent expense management should result in meaningful revenue growth and a greater degree of operating leverage.

Our relationship-oriented banking model, which focuses on high-touch and exceptional level of service, continues to serve us well in a competitive deposit pricing market; noninterest-bearing deposits remained at a very high level, accounting for 43% of our total deposits at year end.

In summary, we believe that we are very well positioned to increase our market share, add attractive new client relationships, generate profitable growth, and further enhance the value of our franchise in 2025 and the coming years.

Sincerely,

SPECIAL NOTE TO OUR SHAREHOLDERSEqually crucial to our Bank’s success are our directors who bring unique perspectives, expertise, and experiences that help shape the future of our organization. For nearly two decades, Board Chair, Willie McDevitt, has served on this Board with distinction and integrity, helping us navigate industry changes and growth, while ensuring we remain true to our foundation: our mission, vision, and guiding principles.This May will mark the end of his chapter as Director. On behalf of the Board, our executive leadership team, and Bank of Marin, I want to express our greatest appreciation to Willie for his years of service and confidence in the future of the Bank and wish him well in all of his future endeavors.​Sincerely,

Notice of Annual Meeting of Shareholders

To Our Shareholders:

Notice is hereby given of the Annual Meeting of Shareholders of Bank of Marin Bancorp. The meeting will be held at 4:00 p.m. Pacific Time on Wednesday, May 21, 2025 at the Bank of Marin Corporate Headquarters, 504 Redwood Boulevard, Suite 100, Novato, California. A reception at the Bank of Marin Corporate Headquarters will immediately follow the Annual Meeting.

You are urged to read the accompanying Proxy Statement carefully. It contains a detailed explanation of all matters on which you will be asked to vote.

Only shareholders of record as of the close of business on April 2, 2025 are entitled to receive notice of and to vote at this meeting.

Your vote is important to us. Whether or not you expect to attend the Annual Meeting, please submit a proxy as soon as possible to instruct how your shares are to be voted at the Annual Meeting. If you participate in and vote your shares at the Annual Meeting, your proxy will not be used.

**If you would like to attend the Annual Meeting, you must pre-register atwww.bankofmarin.com/annual meeting by May 14,**2025. For questions, email events@bankofmarin.com.

Our bylaws provide that nominations for election to the board of directors of the Company may be made by the board of directors or by any shareholder of the Company’s stock entitled to vote for the election of directors. Nominations, other than those made by or on behalf of the existing management of the Company, must be made in writing and delivered or mailed to the Chairman of the Board or the Chief Executive Officer not less than 14 days nor more than 50 days prior to any meeting of shareholders called for the election of directors. The notification of nomination should contain the following information to the extent known by the notifying shareholder: (a) name and address of the proposed nominee(s); (b) principal occupation of the proposed nominee(s); (c) total number of shares that will be voted for the proposed nominee(s); (d) name and residence address of the notifying shareholder; and (e) number of shares owned by the notifying shareholder. Nominations not made in accordance with this section may be disregarded by the Chairman of the meeting, and upon instruction, the Inspector of Election shall disregard all votes cast for each such nominee.

One copy of the Annual Report on Form 10-K and Proxy Statement is being delivered to multiple shareholders sharing an address unless the Company has received contrary instructions from one or more of the shareholders. The Company will deliver promptly upon written or oral request a separate copy of the Annual Report and Proxy Statement to a shareholder at a shared address to which a single copy of the document was delivered. If a shareholder wishes to receive a separate copy or has received multiple copies at one address and would like to receive a single copy in the future, please contact Computershare Trust Company, N.A. by phone at (800) 368-5948 or by written request to Bank of Marin Bancorp c/o Computershare Trust Company, N.A., P.O. Box 43006, Providence, RI 02940-3006. Overnight correspondence should be mailed to Bank of Marin Bancorp c/o Computershare, 150 Royall St., Suite 101, Canton MA 02021. The shareholder website is www.computershare.com/investor.

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE MEETING OF SHAREHOLDERS TO BE HELD ON MAY 21, 2025

Copies of the Annual Meeting Proxy Material, including the Proxy Statement and the Annual Report on Form 10- K, are also available at:www.edocumentview.com/BMRC**.**

By order of the Board of Directors,

Krissy Meyer

Corporate Secretary

April 16, 2025