X0508 4 2024-03-11 0001624322 Business First Bancshares, Inc. BFST 0001841232 McDonald Warren 500 LAUREL STREET, SUITE 101 BATON ROUGE LA 70801 1 Chief Credit Officer 0 COMMON STOCK 2024-03-11 4 M 0 7500 17.11 A 37017 D COMMON STOCK 2024-03-11 4 F 0 5711 22.47 D 31306 D COMMON STOCK 2024-03-11 4 S 0 7000 22.37 D 24306 D STOCK OPTIONS (RIGHT TO BUY) 17.11 2024-03-11 4 M 0 7500 0 D 2024-07-31 Common Stock 7500 0 D Includes (a) 1,354 shares of unvested restricted stock granted on 2/1/2022, which will vest on 3/31/2024, (b) 7,545 shares of unvested restricted stock granted on 2/1/2023, of which 3,716 shares will vest on 3/31/2024 and the remaining 3,829 shares will vest on 3/31/2025, and (c) 8,034 shares of unvested restricted stock granted on 2/1/2024, of which 2,651 shares will vest on 3/31/2024, 2,651 shares will vest on 3/31/2025, and the remaining 2,732 shares will vest on 3/31/2026. Under the terms of the relevant restricted stock grants, the reported shares of unvested restricted stock are subject to forfeiture upon the occurrence of certain events. Stock Options (Right to Buy) were structured to comply with Section 409A of the Internal Revenue Code and are exercised automatically upon the earlier of the expiration date, July 31, 2024, a change in control of the issuer, the reporting person's death or disability, or the reporting person's separation from service, and may not be exercised n any other manner. /s/ Heather Roemer, as attorney-in-fact for Warren McDonald 2024-03-13