Company: OSBC
Filing Date: 2025-05-06
Form Type: S-4/A
Source: 0001104659-25-045103
Chunk: 30

Company: OLD SECOND BANCORP INC
Filing Date: 2025-05-06
Form: S-4/A
Chunk 30
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 of such cash and the fair market value of the Old Second common stock received in the merger, over (ii) the U.S. holder’s adjusted tax basis in the shares of Bancorp Financial common stock surrendered in the merger. With respect to any cash received in lieu of a fractional share of Old Second common stock, a U.S. holder will recognize gain or loss measured by the difference between the amount of cash received for such fractional share and the U.S. holder’s adjusted tax basis in its shares of Bancorp Financial common stock allocable to that fractional share.

For more information, see “Material U.S. Federal Income Tax Consequences of the Merger” beginning on page 76.

#### The Parties (page 102 and 103)

#### Old Second Bancorp, Inc.
37 South River Street 
 Aurora, Illinois 60507 
 (630) 892-0202

Old Second Bancorp, Inc. is a corporation organized under the laws of the State of Delaware in 1981 that serves as the bank holding company for its wholly owned subsidiary bank, Old Second National Bank.

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Old Second National Bank (the “Bank”) is a national banking association headquartered in Aurora, Illinois, that operates through 53 banking centers located in Cook, DeKalb, DuPage, Kane, Kendall, LaSalle and Will counties in Illinois.

Old Second’s common stock is listed on NASDAQ under the symbol “OSBC.” As of December 31, 2024, Old Second had total consolidated assets of $5.65 billion, total loans, net, of $3.94 billion, total deposits of $4.77 billion and total stockholders’ equity of $671.0 million.

More information about Old Second is available by visiting the “Investor Relations” tab of its website at www.oldsecond.com. Information contained on Old Second’s website does not constitute part of, and is not incorporated into, this proxy statement/prospectus. For a complete description of Old Second’s business, financial condition, results of operations and other important information, please refer to Old Second’s filings with the SEC that are incorporated by reference into this document, including its Annual Report on Form 10-K for the year ended December 31, 2024. For more information on documents incorporated by reference into this proxy statement/prospectus and instructions on how to find copies of these documents, see “Where You Can Find More Information” in the forepart of