X0306 4 2019-03-11 0001624322 Business First Bancshares, Inc. BFST 0001734776 HINGLE DONALD A. II 500 LAUREL STREET, SUITE 101 BATON ROUGE LA 70801 1 EVP&CCE of Business First Bank COMMON STOCK 2019-03-11 4 M 0 53 15 A 4969 D COMMON STOCK 2019-03-11 4 S 0 53 24.25 D 4916 D COMMON STOCK 2019-03-12 4 M 0 3000 15 A 7916 D COMMON STOCK 2019-03-12 4 S 0 3000 24 D 4916 D COMMON STOCK 2019-03-13 4 M 0 3000 15 A 7916 D COMMON STOCK 2019-03-13 4 S 0 3000 24.12 D 4916 D COMMON STOCK 2019-03-14 4 M 0 3000 15 A 7916 D COMMON STOCK 2019-03-14 4 S 0 3000 24.26 D 4916 D Stock Options (Right to Buy) 15 2019-03-11 4 M 0 53 0 D 2019-10-19 Common Stock 53 27447 D Stock Options (Right to Buy) 15 2019-03-12 4 M 0 3000 0 D 2019-10-19 Common Stock 3000 24447 D Stock Options (Right to Buy) 15 2019-03-13 4 M 0 3000 0 D 2019-10-19 Common Stock 3000 21447 D Stock Options (Right to Buy) 15 2019-03-14 4 M 0 3000 0 D 2019-10-19 Common Stock 3000 18447 D Reflects the sale of shares in connection with a broker-assisted cashless exercise of Stock Options (Right to Buy) by reporting person. Includes (a) 125 shares of unvested restricted stock granted on 03/31/2017 and (b) 622 shares of unvested restricted stock granted on 03/31/2018, in each case subject to vesting in three equal installments over a period of two years beginning on the grant date and subject to the terms of the relevant restricted stock grant. The reported shares of unvested restricted stock are subject to forfeiture upon the occurrence of certain events specified in the restricted stock grant. Includes 2,500 shares held by reporting person's IRA and units of employer stock fund through issuer's 401(k) plan equivalent to approximately 1,243 shares. This transaction was executed in multiple trades at prices ranging from $24.00 to $24.25. The price reported above reflect the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $24.25 to $24.50. The price reported above reflect the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. Stock Options (Right to Buy) vest in 11 equal installments beginning on the grant date, October 19, 2009, and ending October 19, 2019. /s/ Heather Roemer, as attorney-in-fact 2019-03-14