FIRST BUSINESS FINANCIAL SERVICES, INC. 10-Q

Item 5. Other Information None. Item 6. Exhibits 31.1 Certification of the Chief Executive Officer 31.2 Certification of the Chief Financial Officer 32 Certification of the Chief Executive Officer and Chief Financial Officer pursuant to 18 U.S.C. Section 1350 101 The following financial information from First Business Financial Services, Inc.’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2021, formatted in XBRL (eXtensible Business Reporting Language): (i) Consolidated Balance Sheets as of March 31, 2021 and December 31, 2020, (ii) Consolidated Statements of Income for the three months ended March 31, 2021 and 2020, (iii) Consolidated Statements of Comprehensive Income for the three months ended March 31, 2021 and 2020, (iv) Consolidated Statements of Changes in Stockholders’ Equity for the three months ended March 31, 2021 and 2020, (v) Consolidated Statements of Cash Flows for the three months ended March 31, 2021 and 2020, and (vi) the Notes to Unaudited Consolidated Financial Statements Signatures Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. FIRST BUSINESS FINANCIAL SERVICES, INC. April 30, 2021 /s/ Corey A. Chambas Corey A. Chambas Chief Executive Officer April 30, 2021 /s/ Edward G. Sloane, Jr. Edward G. Sloane, Jr. Chief Financial Officer (principal financial officer) 62