8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): December 15, 2025

MainStreet Bancshares, Inc.

(Exact name of Registrant as Specified in Its Charter)

(703) 481-4567

(Registrant’s Telephone Number, Including Area Code)

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instructions A.2. below):

☐         Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐         Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐         Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐         Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company  ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On December 15, 2025, Ali Reza Manouchehri, a director of Mainstreet Bancshares, Inc. (the "Company") and MainStreet Bank (the "Bank"), notified the Company and the Bank that he is resigning from the Boards of Directors of the Company and the Bank effective January 1, 2026.

Mr. Manouchehri is the Chief Executive Officer of Metrostar Systems LLC, a high-growth government contracting company that was recently sold to Veritas Capital, and their strategic plan requires his full time and attention going forward. Mr. Manouchehri expressed his gratitude to the Directors and conveyed his deep appreciation for the vision, discipline, and culture that have made MainStreet Bank what it is today. Mr. Manouchehri also indicated that he has been a loyal customer of the Bank for over two decades and will remain a steadfast supporter of MainStreet Bank going forward.

Note: As described above, Mr. Manouchehri's decision was for personal reasons and was not the result of any disagreement with the Company or the Bank on any matter relating to the Company’s or the Bank’s operations, policies, practices, financial disclosures, accounting practices or internal controls. It is currently expected that following Mr. Manouchehri’s resignation the size of the Board of Directors of the Company will be reduced from eleven to ten.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.