Material Agreement (Form 8-K)

Item 1.01 Entry into a Material Definitive Agreement.

On June 17, 2026, Enterprise Financial Services Corp (the "Company") completed the issuance and sale (the "Offering") of $175,000,000 aggregate principal amount of its 6.25% Fixed-to-Floating Rate Subordinated Notes due 2036 (the "Notes"). The Offering was completed pursuant to the Company's Registration Statement on Form S-3 (File No. 333-294014) (including a base prospectus) filed with the Securities and Exchange Commission (the "SEC") on March 4, 2026, as supplemented by the prospectus supplement dated June 12, 2026, and filed with the SEC on June 16, 2026.

In connection with the Offering, the Company entered into an Underwriting Agreement, dated June 12, 2026 (the "Underwriting Agreement"), with Keefe, Bruyette & Woods, Inc. and Raymond James & Associates, Inc., as representatives of the several underwriters listed on Schedule A attached thereto. The Notes were sold at an underwriting discount of 1.25%, resulting in net proceeds to the Company of approximately $172.8 million before deducting expenses of the Offering. The Company intends to use the net proceeds from the Offering for general corporate purposes, which may include repayment or redemption of outstanding indebtedness, the payment of dividends, providing capital to support its organic growth or growth through strategic acquisitions, capital expenditures, financing investments, repurchasing shares of its common stock, and for investments in the Company's wholly-owned subsidiary, Enterprise Bank & Trust (the "Bank"), as regulatory capital. The Underwriting Agreement contains customary representations, warranties and covenants and includes the terms and conditions for the sale of the Notes in the Offering, indemnification and contribution obligations and other terms and conditions customary in agreements of this type.

The Notes were issued under the Subordinated Indenture, dated as of June 17, 2026 (the "Base Indenture"), as supplemented by the First Supplemental Indenture, dated as of June 17, 2026 (the "First Supplemental Indenture"), between the Company and U.S. Bank Trust Company, National Association, as trustee.

From and including the date of issuance to, but excluding, July 1, 2031, or earlier redemption date, the Notes will bear interest at an initial fixed rate of 6.25% per annum, payable semi-annually in arrears on January 1 and July 1 of each year, commencing on January 1, 2027. From and including July 1, 2031 to, but excluding the maturity date, July 1, 2036, or earlier redemption date, the Notes will bear interest at a floating rate per annum equal to a benchmark rate, which is expected to be Three-Month Term SOFR (as defined in the First Supplemental Indenture), plus 232 basis points, payable quarterly in arrears on January 1, April 1, July 1 and October 1 of each year, commencing on October 1, 2031. Notwithstanding the foregoing, if the benchmark rate is less than zero, then the benchmark rate shall be deemed to be zero.

The Company may, at its option, redeem the Notes (i) in whole or in part beginning on the interest payment date of July 1, 2031, and on any interest payment date thereafter or (ii) in whole but not in part upon the occurrence of a "Tax Event," a "Tier 2 Capital Event" or the Company becoming required to register as an investment company pursuant to the Investment Company Act of 1940, as amended. The redemption price for any redemption is 100% of the principal amount of the Notes, plus accrued and unpaid interest thereon to, but excluding, the date of redemption. Any redemption of the Notes will be subject to the receipt of the approval of the Board of Governors of the Federal Reserve System to the extent then required under applicable laws or regulations, including capital regulations.