Material Agreement, Private Placement (Form 8-K)

Item 1.01 Entry into a Material Definitive Agreement.

Agreement and Plan of Merger

Overview

On November 30, 2025, Associated Banc-Corp, a Wisconsin corporation ("Associated"), entered into an Agreement and Plan of Merger (the "Merger Agreement") with American National Corporation, a Nebraska corporation ("American National"). The Merger Agreement provides that, upon the terms and subject to the conditions set forth therein, American National will merge with and into Associated (the "Merger"), with Associated surviving the Merger (the "Surviving Corporation"). Immediately following the effective time of the Merger (the "Effective Time") or at such later time and date as Associated may determine in its sole discretion, Associated will cause American National's wholly owned banking subsidiary, American National Bank, to merge with and into Associated's wholly owned banking subsidiary, Associated Bank, National Association (the "Bank Merger"), with Associated Bank, National Association continuing as the surviving bank in the Bank Merger. The Merger Agreement was unanimously approved by the Board of Directors of each of Associated and American National.

Upon the terms and subject to the conditions set forth in the Merger Agreement, at the Effective Time, each share of voting stock, par value $1.00 per share, and each share of non-votingstock, par value $0.01 per share, of American National issued and outstanding immediately prior to the Effective Time, other than certain excepted shares (including those held by American National or Associated, if any), will be converted into the right to receive 36.250 shares (the "Exchange Ratio," and such shares, the "Merger Consideration") of common stock, par value $0.01 per share, of Associated ("Associated Common Stock"). Fractional shares will not be issued; instead, American National shareholders will receive cash in lieu of fractional shares.

Representations and Warranties; Covenants

The Merger Agreement contains customary representations and warranties from both Associated, on the one hand, and American National, on the other hand, and each party has agreed to customary covenants.

Under the Merger Agreement, each of Associated and American National has agreed to use its reasonable best efforts to obtain as promptly as practicable all consents required to be obtained from any governmental authority or other third party to consummate the transactions contemplated by the Merger Agreement (including the Merger and the Bank Merger). Notwithstanding such general obligation, Associated shall not be required to, and American National shall not (without the written consent of Associated), take any action that would reasonably be likely to have a material adverse effect on the Surviving Corporation and its subsidiaries, taken as a whole, after giving effect to the Merger (measured on a scale relative to the size of American National and its subsidiaries, taken as a whole) (a "Materially Burdensome Regulatory Condition").

Governance

Pursuant to the Merger Agreement, effective as of the Effective Time, Associated will cause Wende Kotouc, Executive Co-Chairmanand Chief Executive Officer of American National Bank and Executive Vice President and a member of the board of directors of American National, to be appointed as a director of Associated. If Associated's board of directors will consist of greater than eleven members following its 2026 Annual Meeting of Shareholders, Associated will cause to be appointed effective immediately following such meeting a second mutually agreed American National board member as a director of Associated.

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Closing Conditions

The completion of the Merger is subject to customary conditions, including (1) authorization for listing on the New York Stock Exchange of the shares of Associated Common Stock to be issued in the Merger, subject to official notice of issuance, (2) receipt of regulatory authorizations, consents and approvals, including from the Board of Governors of the Federal Reserve System and the Office of the Comptroller of the Currency, and expiration of all applicable waiting periods in respect thereof, (3) effectiveness of the registration statement on Form S-4for Associated Common Stock to be issued (other than to American National's voting shareholders) in the Merger, and (4) the absence of any order, injunction, decree or other legal restraint preventing the completion of the Merger or the Bank Merger or making the completion of the Merger or the Bank Merger illegal. Each party's obligation to complete the Merger is also subject to certain additional customary conditions, including (i) subject to certain materiality qualifications, the accuracy of the representations and warranties of the other party, (ii) performance in all material respects by the other party of its obligations under the Merger Agreement and (iii) receipt by such party of an opinion from its respective counsel to the effect that the Merger will qualify as a reorganization within the meaning of Section 368(a) of the Internal Revenue Code of 1986, as amended. In addition, Associated's obligation to complete the Merger is subject to receipt from American National of a properly executed Foreign Investment and Real Property Tax Act of 1980 notification letter and absence of any Materially Burdensome Regulatory Condition, and each party's obligation to complete the Merger is subject to the absence of any breach or intended breach of certain ancillary agreements described further in the Merger Agreement.

Termination

The Merger Agreement provides certain termination rights for both Associated and American National (a) by mutual written consent of Associated and American National, (b) by either Associated or American National if there is a final injunction, order or decree prohibiting or making illegal the consummation of the Merger or the Bank Merger, (c) by either Associated or American National if the Merger has not been consummated by November 30, 2026, unless such date is amended by mutual written agreement of Associated and American National, or (d) by either Associated or American National (provided that the terminating party is not then in material breach of any representation, warranty, obligation, covenant or other agreement contained in the Merger Agreement) if there has been an uncured or incurable breach by the other party of any of its representations or covenants that would result in the failure of a closing condition.

Important Statement Regarding Merger Agreement

The foregoing description of the Merger Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Merger Agreement, which is attached hereto as Exhibit 2.1 and is incorporated herein by reference.

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The representations, warranties and covenants of each party set forth in the Merger Agreement have been made only for the purposes of, and were and are solely for the benefit of the parties to, the Merger Agreement, may be subject to limitations agreed upon by the contracting parties, including being qualified by confidential disclosures made for the purposes of allocating contractual risk between the parties to the Merger Agreement instead of establishing these matters as facts, and may be subject to standards of materiality applicable to the parties that differ from those applicable to investors. Accordingly, the representations and warranties may not describe the actual state of affairs at the date they were made or at any other time, and investors should not rely on them as statements of fact. In addition, such representations and warranties (1) will not survive consummation of the Merger, and (2) were made only as of the date of the Merger Agreement or such other date as is specified in the Merger Agreement. Moreover, information concerning the subject matter of the representations and warranties may change after the date of the Merger Agreement, which subsequent information may or may not be fully reflected in the parties' public disclosures. Accordingly, the Merger Agreement is included with this filing only to provide investors with information regarding the terms of the Merger Agreement, and not to provide investors with any factual information regarding Associated or American National, their respective affiliates or their respective businesses. The Merger Agreement should not be read alone, but should instead be read in conjunction with the other information regarding Associated, American National, their respective affiliates or their respective businesses, the Merger Agreement and the Merger that will be contained in, or incorporated by reference into, the registration statement on Form S-4that will include a prospectus of Associated, as well as in the Annual Reports on Form 10-K,Quarterly Reports on Form 10-Qand other filings that Associated makes with the Securities and Exchange Commission (the "SEC").

Transfer, Voting and Registration Rights Agreement

Concurrently with the execution and delivery of the Merger Agreement, the voting shareholders of American National have entered into a Transfer, Voting and Registration Rights Agreement (the "Shareholders' Agreement") pursuant to which, among other things, each American National voting shareholder delivered its executed written consent to adopt the Merger Agreement, agreed to comply with certain transfer restrictions with respect to the Associated Common Stock they will receive in the Merger and agreed, subject to limited exceptions, to vote their shares of Associated Common Stock in accordance with the recommendation of the Associated board of directors, and Associated agreed to register such shares of Associated Common Stock on the terms and subject to the conditions set forth in the Shareholders' Agreement. The transfer restrictions prohibit transfers of Associated Common Stock in the first sixty days following the completion of the merger and, for the remainder of the period through the first anniversary, among other things, limits the public sale of shares to 150,000 shares per day (unless pursuant to a broadly distributed underwritten offering). The transfer and voting obligations will terminate at such time when the former American National voting shareholders cease to hold at least 5% of outstanding Associated voting securities, and each such shareholder's registration rights will terminate once such shareholder no longer holds any registrable securities of Associated.

The foregoing description of the Shareholders' Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Shareholders' Agreement, which is attached hereto as Exhibit 10.1 and incorporated herein by reference.

Item 3.02 Unregistered Sales of Equity Securities.

The information set forth under Item 1.01 of this Report on Form 8-Kwith respect to the issuance of Associated Common Stock to the American National voting shareholders is incorporated herein by reference. The issuance of the Associated Common Stock to American National voting shareholders in the Merger is expected to be exempt from the registration requirements of the Securities Act of 1933, as amended (the "Securities Act"), under Section 4(a)(2) of the Securities Act.

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