X0508 4 2026-03-01 0001624322 Business First Bancshares, Inc. BFST 0001889385 Strong Saundra 500 LAUREL STREET, SUITE 101 BATON ROUGE LA 70801 1 EVP & General Counsel 0 COMMON STOCK 2026-03-01 4 M 0 1338 A 8046 D COMMON STOCK 2026-03-01 4 F 0 295 27.30 D 7751 D COMMON STOCK 2026-03-01 4 D 0 669 27.30 D 7082 D Restricted Stock Units 2026-03-01 4 M 0 1338 D Common Stock 1338 5298 D Restricted Stock Units 0 2026-03-02 4 A 0 815 A Common Stock 815 6113 D Restricted Stock Units 0 2026-03-02 4 A 0 3264 A Common Stock 3264 9377 D Includes 2,732 shares of unvested restricted stock granted on February 1, 2024, which will vest on March 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. The reporting person received an award of 4,052 time-based restricted stock units on March 1, 2025, vesting in three substantially equal installments on the first, second, and third anniversary of the issuance date. These shares were acquired upon the partial vesting of the previously reported time-based restricted stock units granted to the reporting person on March 1, 2025. The reporting person has irrevocably elected to defer the reported securities under the b1BANK Deferred Compensation Plan (the "Deferred Compensation Plan"). In accordance with the Deferred Compensation Plan, the reporting person will receive a lump sum cash distribution in an amount equal to the vested securities deferred under the Deferred Compensation Plan, plus any earnings or losses attributable thereto, on the first business day following the month in which the reporting person's separation of service, death, or disability occurs. Reflects the grant of 815 time-based restricted stock units granted to the reporting person on March 2, 2026, of which 271 shares will vest on March 2, 2027, 271 shares will vest on March 2, 2028, and the remaining 273 shares will vest on March 2, 2029. Each time-based restricted stock unit is economically equivalent to one share of common stock of the issuer. Reflects the grant of 3,264 time-based restricted stock units granted to the reporting person on March 2, 2026, of which 1,088 shares will vest on March 2, 2027, 1,088 shares will vest on March 2, 2028, and the remaining 1,088 shares will vest on March 2, 2029. Each time-based restricted stock unit is economically equivalent to one share of common stock of the issuer. The reporting person has irrevocably elected to defer the reported securities under the Deferred Compensation Plan. In accordance with the Deferred Compensation Plan, the reporting person will receive a lump sum cash distribution in an amount equal to the vested securities deferred under the Deferred Compensation Plan, plus any earnings or losses attributable thereto, on the first business day following the month in which the reporting person's separation of service, death, or disability occurs. Includes: (a) 2,584 time-based restricted stock units granted to the reporting person on December 12, 2024, which will vest in two substantially equal installments on the second and third anniversary of the issuance date; (b) 2,714 time-based restricted stock units granted to the reporting person on March 1, 2025, which will vest in two substantially equal installments on the second and third anniversary of the issuance date; (c) 815 time-based restricted stock units granted to the reporting person on March 2, 2026, which will vest in three substantially equal installments on the first, second, and third anniversary of the issuance date; and (d) 3,264 time-based restricted stock units, which will vest in three substantially equal installments on the first, second, and third anniversary of the issuance date. /s/ Heather Roemer, as attorney-in-fact for Saundra Strong 2026-03-03