X0508 4 2026-02-23 0000836147 MIDDLEFIELD BANC CORP MBCN 0001806753 Voinovich Michael C 15985 EAST HIGH STREET MIDDLEFIELD OH 44062 1 0 Common Stock 2026-02-23 4 A 0 405 35.18 A 3527.425 D Common Stock 9252.7970 I held in IRA Common Stock 768.78 I held in IRA Common Stock 1500 I held in IRA (McD) Common Stock 2402.1040 I held in Roth IRA Common Stock 8965 I held in Rabbi Trust Includes shares acquired under MBCN Dividend Reinvestment Plan The shares represent accelerated vesting of restricted stock units (RSUs) granted on June 27, 2025. On February 23, 2026, the Compensation Committee of Middlefield's Board of Directors approved 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. /s/ Michael C. Voinovich by Julie E. Shaw Power of Attorney 2026-02-25