X0508 4 2025-12-17 0000836147 MIDDLEFIELD BANC CORP MBCN 0001698885 Erminio Courtney M 15985 EAST HIGH STREET MIDDLEFIELD OH 44062 1 EVP/Chief Risk Officer 0 Common Stock 2025-12-17 4 A 0 2035 37 A 6471.991 D Common Stock 2025-12-17 4 A 0 2204 37 A 8675.991 D Common Stock 2025-12-17 4 F 0 1202 37 D 7473.991 D Common Stock 150.525 D Conditional Stock Award 2027-09-06 Common Stock 1708 1708 D Conditional Stock Award 2028-01-14 Common Stock 2828 2828 D Amendment of conditional stock award agreement resulting in acceleration of restricted stock grants. The restricted stock award was originally granted on March 10, 2023, and provides for vesting on the third anniversary of the award. Amendment of performance share unit award agreement resulting in acceleration of performance share unit grants. The performance share unit award was originally granted on August 6, 2024, and provides for vesting in any earned performance share units upon the payment date, defined as within sixty days after December 31, 2026. Includes shares acquired under MBCN Dividend Reinvestment Plan Includes shares held jointly with spouse. The award represents a grant of restricted stock which vests ratably over a three-year period provided that Mrs. Erminio 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. The details of the vesting conditions may be found in a Form 8-K dated September 4, 2024. The award represents a grant of restricted stock which vests ratably over a three-year period provided that Mrs. Erminio 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. the details of the vesting conditions may be found in a Form 8-K dated January 17, 2025. Each restricted stock unit represents the right to receive, at settlement, one share of common stock. /s/ Courtney M. Erminio by Julie E. Shaw Power of Attorney 2025-12-18