0000357173 2026-08-13 2026-08-13 0000357173 1 2026-08-13 2026-08-13 0000357173 2 2026-08-13 2026-08-13 0000357173 3 2026-08-13 2026-08-13 0000357173 4 2026-08-13 2026-08-13 0000357173 5 2026-08-13 2026-08-13 0000357173 6 2026-08-13 2026-08-13 0000357173 7 2026-08-13 2026-08-13 0000357173 8 2026-08-13 2026-08-13 0000357173 9 2026-08-13 2026-08-13 0000357173 10 2026-08-13 2026-08-13 0000357173 11 2026-08-13 2026-08-13 0000357173 12 2026-08-13 2026-08-13 0000357173 13 2026-08-13 2026-08-13 0000357173 14 2026-08-13 2026-08-13 0000357173 15 2026-08-13 2026-08-13 0000357173 16 2026-08-13 2026-08-13 0000357173 17 2026-08-13 2026-08-13 0000357173 18 2026-08-13 2026-08-13 0000357173 19 2026-08-13 2026-08-13 iso4217:USD pure S-3 S-3ASR EX-FILING FEES 0000357173 OLD SECOND BANCORP INC N/A N/A S-3 OLD SECOND BANCORP INC false Equity Common Stock, par value $1.00 per share true 0.0001381 false Equity Preferred Stock, par value $1.00 per share true 0.0001381 false Equity Depositary Shares true 0.0001381 false Debt Debt Securities true 0.0001381 false Other Stock Purchase Contracts true 0.0001381 false Other Stock Purchase Units true 0.0001381 false Other Warrants true 0.0001381 false Other Subscription Rights true 0.0001381 false Other Units true 0.0001381 Equity Common Stock, par value $1.00 per share true S-3 333-274068 2023-08-28 Equity Preferred Stock, par value $1.00 per share true S-3 333-274068 2023-08-28 Equity Depositary Shares true S-3 333-274068 2023-08-28 Debt Debt Securities true S-3 333-274068 2023-08-28 Other Stock Purchase Contracts true S-3 333-274068 2023-08-28 Other Stock Purchase Units true S-3 333-274068 2023-08-28 Other Warrants true S-3 333-274068 2023-08-28 Other Subscription Rights true S-3 333-274068 2023-08-28 Other Units true S-3 333-274068 2023-08-28 Unallocated (Universal) Shelf true 200000000.00 S-3 333-274068 2023-08-28 22040.00 200000000.00 0.00 0.00 0.00 0.00 The securities covered by this registration statement may be sold or otherwise distributed separately, together or as units with other securities covered by this registration statement. In accordance with Rules 456(b) and 457(r) under the Securities Act, the Registrant is deferring payment of all registration fees relating to newly registered securities. In connection with securities offered hereby, the Registrant will pay registration fees on a "pay-as-you-go" basis in accordance with Rule 456(b), calculated using the fee payment rate in effect on the date of payment. An unspecified aggregate initial offering price or number of the securities of each identified class is being registered as may from time to time be offered at unspecified prices by the Registrant. Separate consideration may or may not be received for securities that are issuable upon exercise, settlement, conversion or exchange of other securities or that are issued in units with other securities registered hereunder. In addition, pursuant to Rule 416(a) under the Securities Act, this registration statement covers any additional securities that may be offered or issued in connection with any stock split, stock dividend or other similar transaction. See Note (1). See Note (1). See Note (1). This registration statement covers senior and subordinated debt securities. See Note (1). See Note (1). See Note (1). See Note (1). See Note (1). Pursuant to Rule 415(a)(6) under the Securities Act, this registration statement includes securities having a maximum aggregate offering price of $200,000,000 that were previously registered and remain unsold under the Registrant's Registration Statement on Form S-3 (File No. 333-274068), initially filed on August 18, 2023 and declared effective on August 28, 2023 (the "Prior Registration Statement") (the "Carry Forward Securities"). No securities were sold pursuant to the Prior Registration Statement. The $22,040 filing fee previously paid with respect to the Carry Forward Securities is being carried forward to this registration statement and will continue to be applied to the Carry Forward Securities. Accordingly, no additional filing fee is due with respect to the Carry Forward Securities. Pursuant to Rule 415(a)(6), the offering of the Carry Forward Securities under the Prior Registration Statement will be deemed terminated as of the effectiveness of this registration statement.