X0508 4 2024-09-16 0000836147 MIDDLEFIELD BANC CORP MBCN 0001954793 Zimmerly Ronald Len Jr. 15985 EAST HIGH STREET MIDDLEFIELD OH 44062 1 1 Chief Executive Officer 0 Common Stock 2024-09-16 4 P 0 212.283 28.47 A 31289.283 D Common Stock 8786 I Held in IRA Conditional Stock Award 2027-08-30 Common Stock 6708 6708 D Conditional Stock Award 27.4000 2026-03-10 Common Stock 3722 3722 D Conditional Stock Award 28.6000 2025-12-01 Common Stock 7576 7576 D Includes shares acquired under MBCN Dividend Reinvestment Plan The award represents a grant of restricted stock which vests ratably over a three-year period provided that Mr. Zimmerly remains continuously employed by Middlefield as of each vesting date. Until the award vests, the award confers no right to vote, no right to dividends, and no other shareholder rights to the recipient. Each restricted stock unit represents the right to receive, at settlement, one share of common stock. Until the award vests, the award confers no right to vote, no right to dividends, and no other shareholder rights to the recipient. Vesting is subject to a time-based or service condition and a performance-based condition. The details of the vesting conditions may be found in a Form 8K filing dated March 17, 2023. The award represents a grant of restricted stock which vests ratably over a three-year period provided that Mr. Zimmerly remains continuously employed by Middlefield as of each vesting date. Until the award vests, the award confers no right to vote, no right to dividends, and no other shareholder rights to the recipent. /s/ Ronald L. Zimmerly, Jr. by Julie E. Shaw Power of Attorney 2024-09-19