8-K

UNITED

STATES

SECURITIES

AND EXCHANGE COMMISSION

Washington,

D.C. 20549

FORM 8-K

Current Report

Pursuant

to Section 13 OR 15(d) of the Securities Exchange Act of 1934

Dateof Report (Date of earliest event reported): April 26, 2024

FirstBusiness Financial Services, Inc.

(Exact name of registrant as specified in its charter)

401 Charmany Drive

Madison, Wisconsin 53719

(Address of principal executive offices) (Zip code)

Registrant’s

telephone number, including area code: (608) 238-8008

N/A

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicateby check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b- 2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).         Emerging growthcompany ¨

If an emerginggrowth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with anynew or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

On April 26, 2024, First Business Financial Services, Inc. (the “Company”) held its Annual Meeting of Shareholders (the “Annual Meeting”) to: (1) elect three Class II directors to hold office until the 2027 annual meeting of shareholders and until their successors are duly elected and qualified; (2) approve in a non-binding advisory vote the compensation of the Company’s named executive officers; and (3) ratify the appointment of Crowe LLP as the Company’s independent registered public accounting firm for the year ending December 31, 2024.

Of the aggregate 8,306,543 shares of the Company’s common stock issued and outstanding as of the close of business on the record date, February 28, 2024, 6,431,288 shares or 77% were represented in person or by proxy at the Annual Meeting.

At the Annual Meeting, the Company’s shareholders voted as follows:

The three nominees listed above were elected by a plurality to serve on the Board. Further, each nominee received in excess of 97% of the shares voted in favor of their election.

This matter was approved by shareholders with 92% of shares voted cast in favor of the proposal.

This matter was approved by shareholders with 99% of shares voted cast in favor of the proposal.

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 hereunto duly authorized.

Exhibit 99.1