Sarah A. Winters - 23 Feb 2026 Form 4 Insider Report for MIDDLEFIELD BANC CORP (MBCN)

Role: EVP/CHRO
Signature: /s/ Sarah A. Winters by Julie E. Shaw Power of Attorney
Issuer symbol: MBCN
Transactions as of: 23 Feb 2026
Net transactions value: +$336,075
Form type: 4
Filing time: 25 Feb 2026, 16:08:01 UTC
Previous filing: 16 Jan 2026
Next filing: 02 Mar 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Winters Sarah A	EVP/CHRO	15985 EAST HIGH STREET, MIDDLEFIELD	/s/ Sarah A. Winters by Julie E. Shaw Power of Attorney	25 Feb 2026	0002008413

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	MBCN	Common Stock	Award	$60,087	+1,708	+35%	$35.18	6,618	23 Feb 2026	Direct	F1
transaction	MBCN	Common Stock	Award	$66,349	+1,886	+28%	$35.18	8,504	23 Feb 2026	Direct	F2
transaction	MBCN	Common Stock	Award	$70,325	+1,999	+24%	$35.18	10,503	23 Feb 2026	Direct	F3
transaction	MBCN	Common Stock	Award	$279,822	+7,954	+76%	$35.18	18,457	23 Feb 2026	Direct	F4
transaction	MBCN	Common Stock	Tax liability	$140,509	-3,994	-22%	$35.18	14,463	23 Feb 2026	Direct

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The shares represent accelerated vesting of restricted stock units ("RSUs") resulting from action of the Middlefield Compensation Committee on February 23, 2026, approving the full vesting of all outstanding plan share awards, including the RSUs. For further information regarding the acceleration of the RSUs, please see the Form 8-K Current Report filed by Middlefield with the SEC on February 25, 2026. The restricted stock award was originally granted on September 4, 2024, and provides for vesting on the third anniversary of the award.
F2	The shares represent accelerated vesting of RSUs resulting from Compensation Committee approval on February 23, 2026. See the Form 8-K Current Report filed by Middlefield with the SEC on February 25, 2026. The restricted stock award was originally granted on January 17, 2025, and provides for vesting on the third anniversary of the award.
F3	The shares represent accelerated vesting of performance share units ("PSUs") resulting from action of the Middlefield Compensation Committee on February 23, 2026, approving the full vesting of all outstanding plan share awards, including the PSUs. See the Form 8-K Current Report filed by Middlefield with the SEC on February 25, 2026. The vesting conditions at grant were described in a Form 8-K filed on September 4, 2024.
F4	The shares represent accelerated vesting of PSUs resulting from action of the Middlefield Compensation Committee on February 23, 2026. See the Form 8-K Current Report filed by Middlefield with the SEC on February 25, 2026. The vesting conditions at grant were described in a Form 8-K filed on January 17, 2025.