# EDGAR Filing Document

**Accession Number:** 0001521951
**File Stem:** 0001104659-26-025239
**Filing Date:** 2026-3
**Character Count:** 3639
**Document Hash:** c76d3a62807fc9e1d6c4d185ac03dd83
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-26-025239.hdr.sgml**: 20260309

**ACCESSION NUMBER**: 0001104659-26-025239

**CONFORMED SUBMISSION TYPE**: DEFA14A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260309

**DATE AS OF CHANGE**: 20260309

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** FIRST BUSINESS FINANCIAL SERVICES, INC.
- **CENTRAL INDEX KEY:** 0001521951
- **STANDARD INDUSTRIAL CLASSIFICATION:** STATE COMMERCIAL BANKS [6022]
- **ORGANIZATION NAME:** 02 Finance
- **EIN:** 391576570
- **STATE OF INCORPORATION:** WI
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** DEFA14A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-34095
- **FILM NUMBER:** 26735260

**BUSINESS ADDRESS:**
- **STREET 1:** 401 CHARMANY DRIVE
- **CITY:** MADISON
- **STATE:** WI
- **ZIP:** 53719
- **BUSINESS PHONE:** 608-238-8008

**MAIL ADDRESS:**
- **STREET 1:** 401 CHARMANY DRIVE
- **STREET 2:** PO BOX 44961
- **CITY:** MADISON
- **STATE:** WI
- **ZIP:** 53744

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** First Business Financial Services, Inc.
- **DATE OF NAME CHANGE:** 20110527

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**WASHINGTON, D.C. 20549**

**SCHEDULE 14A INFORMATION**

Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

(Amendment No.)

Filed by the Registrant ⌧

Filed by a Party other than the Registrant ◻

Check the appropriate box:

◻ Preliminary Proxy Statement

◻ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

◻ Definitive Proxy Statement

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;⌧ Definitive
Additional Materials

◻ Soliciting Material Pursuant to §240.14a-12

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| |
|:---|
| **First Business Financial Services, Inc.** |
| (Name of Registrant as Specified in its Charter) |
| (Name of Person(s) Filing Proxy Statement if other than the Registrant) |

---

Payment of Filing Fee (Check all boxes that apply):

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;⌧ No
fee required

◻ Fee paid previously with preliminary materials

◻ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11

**FIRST BUSINESS FINANCIAL SERVICES, INC.**

**Supplement No. 1 to**

**Proxy Statement dated March 5, 2026**

This Supplement No. 1 to the Proxy Statement of First Business Financial Services, Inc. (the "Company"), filed on Schedule 14A with the Securities and Exchange Commission on March 5, 2026 (the "Proxy Statement") in connection with the Annual Meeting of Shareholders to be held on April 24, 2026, is being filed solely for the purpose of adding the information provided below with respect to Item 2: Approval of the 2026 Equity Incentive Plan ("Item 2") beginning on page 24 of the Proxy Statement.

Item 2 is hereby supplemented to include the following information:

Adoption of the 2026 Equity Incentive Plan requires the affirmative vote of a majority of the votes cast on the matter at the Annual Meeting, assuming a quorum is present. Because this proposal is considered a non-routine matter, brokers will not have discretion to vote uninstructed shares. Abstentions and broker non-votes will not be considered votes cast and therefore will have no effect on the outcome of the proposal.

This Supplement does not revise or update any other information set forth in the Proxy Statement, and it should be read in conjunction with the Proxy Statement. From and after the date of this supplement, any references to the "Proxy Statement" are to the Proxy Statement as supplemented hereby.

The date of this Proxy Statement Supplement is March 9, 2026.