X0407 4 2023-05-02 0001624322 Business First Bancshares, Inc. BFST 0001734773 MANSFIELD KEITH 500 LAUREL STREET, SUITE 101 BATON ROUGE LA 70801 1 EVP&COO of b1Bank 0 COMMON STOCK 2023-05-02 4 P 0 8500 14.59 D 62727 D COMMON STOCK 2023-05-03 4 P 0 1500 14.60 D 64227 D Includes (a) 3,116 shares of unvested restricted stock granted on 2/1/2022, which will vest on 3/31/2024, and (b) 10,838 shares of restricted stock granted on 2/1/2023, of which 5,338 shares will vest on 3/31/2024 and the remaining 5,500 shares will vest on 3/31/2025. 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. Includes 5,000 shares held by reporting person's IRA. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $14.55 to $14.60, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or Commission staff, upon request, full information regarding the number of shares sold at each separate price within this range. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $14.56 to $14.60, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or Commission staff, upon request, full information regarding the number of shares sold at each separate price within this range. /s/ Heather Roemer, as attorney-in-fact for Keith Mansfield 2023-05-05