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The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."}],"balance_after":250589,"source":{"system":"sec-edgar","filing":"0002074132-26-000008","document":"form4-09032026_090942.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2074132/000207413226000008/form4-09032026_090942.xml","form_type":"4"}},{"id":886723,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2239,"kind":"person","name":"Campbell Darin Patrick","position":1,"cik":"0002074132","reported_name":"Campbell Darin Patrick","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"President, Powersports Lending"}}],"security":"Restricted Stock","published_at":"2026-02-24T23:44:39.000Z","date":"2026-02-17","kind":"grant","planned":false,"acquired":true,"shares":10562,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Each restricted stock unit represents a contingent right to receive one share of common stock. The reporting person was granted 10,562 restricted stock units on the date of the grant, 5,281 of which are time-based restricted stock units that vest on the third anniversary of the grant date, and 5,281 of which are performance-based restricted stock units that may vest and convert to shares within a range from 0% to 175% of the underlying performance-based restricted stock units originally awarded, depending on our compensation committee approved performance metrics. 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The reporting person held 22,300 shares of Bancorp Financial, Inc., which pursuant to the merger agreement was converted into 57,565 shares of Old Second Bancorp, Inc. common stock. These shares are held in a custodial account in an IRA on behalf of the reporting person. The exchange of shares occurred on July 19, 2025."}],"balance_after":57565,"source":{"system":"sec-edgar","filing":"0001415889-25-020082","document":"form4-07212025_090707.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000141588925020082/form4-07212025_090707.xml","form_type":"4"}}]}