Company: ASB
Filing Date: 2025-12-01
Form Type: 425
Source: 0000007789-25-000189
Chunk: 0

Company: ASSOCIATED BANC-CORP
Filing Date: 2025-12-01
Form: 425
Chunk 0
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 representing 1/40th intrst in a shr of 5.875% Non-Cum. Perp Pref Stock, Srs E |     | ASB PrE           |     | New York Stock Exchange                   |
| Depositary Shrs, each representing 1/40th intrst in a shr of 5.625% Non-Cum. Perp Pref Stock, Srs F |     | ASB PrF           |     | New York Stock Exchange                   |
| 6.625% Fixed-Rate Reset Subordinated Notes due 2033                                                 |     | ASBA              |     | New York Stock Exchange                   |

<div align='center'>Indicate by 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 growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐</div>

| ADDITIONAL INFORMATION AND WHERE TO FIND IT                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
 In connection with the proposed transaction, Associated will file relevant materials with the SEC, including a registration statement on Form S-4 that will include a prospectus of Associated. SHAREHOLDERS OF AMERICAN NATIONAL ARE URGED TO READ THE REGISTRATION STATEMENT WHEN IT BECOMES AVAILABLE, TOGETHER WITH ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC, INCLUDING ANY AMENDMENTS OR SUPPLEMENTS TO THOSE DOCUMENTS, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION. Shareholders will be able to obtain a free copy of the registration statement, as well as other filings containing information about Associated, without charge, at the SEC’s website (http://www.sec.gov) and Associated’s website (https://investor.associatedbank.com/financials/sec-filings/default.aspx). Copies of the registration statement, when available, and the filings with the SEC that will be incorporated by reference in the registration statement can also be obtained, without charge, by directing a request in writing to Associated Banc-Corp, Attn: Investor Relations, 433 Main Street, Green Bay, WI 54301 or by email to