UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Rule 13d-101)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO § 240.13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO

§ 240.13d-2(a)

(Amendment No. 4)¹

Bank of Marin Bancorp

(Name of Issuer)

Common Stock

(Title of Class of Securities)

063425102

(CUSIP Number)

STEVE WOLOSKY, ESQ.

OLSHAN FROME WOLOSKY LLP

1325 Avenue of the Americas

New York, New York 10019

(212) 451-2300

(Name, Address and Telephone Number of Person

Authorized to Receive Notices and Communications)

May 19, 2021

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box ¨.

Note:  Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits.  See § 240.13d-7 for other parties to whom copies are to be sent.

1              The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

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

The following constitutes Amendment No. 4 to the Schedule 13D filed by the undersigned (“Amendment No. 4”). This Amendment No. 4 amends the Schedule 13D as specifically set forth herein.

Item 3 is hereby amended and restated in its entirety to read as follows:

As set forth in Item 5 below, as of May 21, 2021, the Reporting Persons no longer beneficially own any shares of common stock of the Issuer.

Item 5 is hereby amended and restated in its entirety to read as follows:

(a, b, d) As of the close of business on May 21, 2021, none of the Reporting Persons beneficially owned any shares of common stock of the Issuer.

(c) The transactions in the common stock of the Issuer by the Reporting Persons since the filing of Amendment No. 3 are set forth on Schedule A attached hereto, which is incorporated herein by reference.

(e) On May 19, 2021, the Reporting Persons ceased to beneficially own more than 5% of the outstanding shares of common stock of the Issuer.

SIGNATURE

After reasonable inquiry and to the best of my knowledge, I certify that the information set forth in this statement is true, complete and correct.

SCHEDULE A

Transactions in Securities of the Issuer Since the Filing of Amendment No. 3 to the Schedule 13D

The Jon S. Kelly ADMINISTRATIVE Trust

¹ Represents a distribution to a beneficiary of the Trust for no consideration.

² Represents a distribution to a beneficiary of the Trust for no consideration.