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Table of Contents 冈 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 or □ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from Title of each class Common Stock FORM 10 - K Commission file number 000-26719 ( State or other jurisdiction of incorporation or organization ) 310 Leonard Street NW , Grand Rapids , Michigan ( Address of principal executive offices ) to MERCANTILE BANK CORPORATION ( Exact name of registrant as specified in its charter ) Michigan Trading Symbol ( s ) MBWM ( 616 ) 406-3000 ( Registrant's telephone number , including area code ) Securities registered pursuant to Section 12 ( b ) of the Act : ( I.R.S. Employer Identification No. ) 38-3360865 49504 ( Zip Code ) Name of each exchange on which registered The Nasdaq Stock Market LLC Securities registered pursuant to Section 12 ( g ) of the Act : None Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes No Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Act . Yes No 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 . Yes No Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes > No Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , a smaller reporting company or emerging growth company ( as defined in Rule 12b - 2 of the Exchange Act ) . Emerging growth company Accelerated filer > Large accelerated filer Non - accelerated filer Smaller reporting company a If an emerging growth company , indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13 ( a ) of the Exchange Act . □ DOCUMENTS INCORPORATED BY REFERENCE Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404 ( b ) of the Sarbanes Oxley Act ( 15 USC.7262 ( b ) ) by the registered public accounting firm that prepared or issued its audit report . Yes > No Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Act ) . Yes No The aggregate value of the common equity held by non - affiliates ( persons other than directors and executive officers ) of the registrant , computed by reference to the closing price of the common stock as of the last business day of the registrant's most recently completed second fiscal quarter , was approximately $ 356 million . As of February 26 , 2021 , there were issued and outstanding 16,258,947 shares of the registrant's common stock .