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Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 X ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 1934 FORM 10 - K ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF Title of each class or For the transition period from Louisiana ( State or other jurisdiction of incorporation or organization ) 500 Laurel Street , Suite 101 Baton Rouge , Louisiana ( Address of principal executive offices ) Commission file number : 001-38447 BUSINESS FIRST BANCSHARES , INC . ( Exact name of registrant as specified in its charter ) to Trading Symbol ( s ) 20-5340628 ( I.R.S. Employer Identification Number ) ( 225 ) 248-7600 ( Registrant's telephone number , including area code ) Securities registered under Section 12 ( b ) of the Exchange Act : BFST 70801 ( Zip code ) Name of each exchange on which registered Nasdaq Global Select Market Common Stock , par value $ 1.00 per share Securities registered under Section 12 ( g ) of the Exchange Act : None Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Yes Act . Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Yes Act . Indicate by check mark whether the registrant : ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 during the preceding 12 months ( or for such shorter period that the registrant was required to file such reports ) , and ( 2 ) has been subject to such filing requirements for the past 90 days . Note - Checking the box above will not relieve any registrant required to file reports pursuant to Section 13 or 15 ( d ) of the Exchange Act from their obligations under those Sections . Indicate by check mark whether the registrant has submitted electronically every Interactive Date File required to be submitted pursuant to Rule 405 of Regulation S - T ( §232.405 of this chapter ) during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes > No X Yes X No X No No Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , smaller reporting company , or an emerging growth company . See the definitions of “ large accelerated filer , ” “ accelerated filer , ” “ smaller reporting