{"transactions":[{"id":3549206,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2026-09-08T21:17:38.000Z","date":"2026-09-08","kind":"sale","planned":false,"acquired":false,"shares":25000,"price":25.6307,"value":640767.5,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"The price reported is a weighted average price. The transactions were effected at prices ranging from $25.63 to $25.655, inclusive."}],"balance_after":135351,"source":{"system":"sec-edgar","filing":"0001184764-26-000008","document":"form4-09082026_090934.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1184764/000118476426000008/form4-09082026_090934.xml","form_type":"4"}},{"id":3251,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2026-09-03T21:40:25.000Z","date":"2026-09-03","kind":"sale","planned":false,"acquired":false,"shares":25000,"price":25.727,"value":643175.0,"ownership":{"direct":true},"footnotes":[{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F1","text":"The reporting person moved 3,077 shares that were previously held in his account from within Old Second Bancorp, Inc., as reported on a Form 4 filing dated February 24, 2026, to his brokerage account. The total shown reflects the addition of the 3,077 shares when combined with the sale of 25,000 shares."}],"balance_after":135351,"source":{"system":"sec-edgar","filing":"0001184764-26-000004","document":"form4-09032026_090921.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1184764/000118476426000004/form4-09032026_090921.xml","form_type":"4"}},{"id":886747,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Restricted Stock Units","published_at":"2026-02-25T00:24:56.000Z","date":"2026-02-21","kind":"tax_withholding","planned":false,"acquired":false,"shares":3077,"price":20.57,"value":63293.89,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F2","text":"Represents shares vested upon the third anniversary of the date of grant previously reported and are now issued and added to the reporting person's common stock holdings outright."}],"balance_after":10595,"source":{"system":"sec-edgar","filing":"0001184764-26-000002","document":"form4-02252026_120252.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/357173/000118476426000002/form4-02252026_120252.xml","form_type":"4"}},{"id":886746,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Restricted Stock Units","published_at":"2026-02-25T00:24:56.000Z","date":"2026-02-17","kind":"grant","planned":false,"acquired":true,"shares":3121,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"These represent restricted stock units granted pursuant to the Old Second Bancorp, Inc. Long Term Incentive Plan. These shares have a three-year cliff vesting."}],"balance_after":13672,"source":{"system":"sec-edgar","filing":"0001184764-26-000002","document":"form4-02252026_120252.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000118476426000002/form4-02252026_120252.xml","form_type":"4"}},{"id":1254384,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Restricted Stock Units","published_at":"2025-02-21T21:07:31.000Z","date":"2025-02-19","kind":"grant","planned":false,"acquired":true,"shares":3190,"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 3,190 restricted stock units on the date of the grant. These shares are time-based restricted stock units that vest on the third anniversary of the grant date."}],"balance_after":10551,"source":{"system":"sec-edgar","filing":"0001415889-25-005047","document":"form4-02212025_090227.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000141588925005047/form4-02212025_090227.xml","form_type":"4"}},{"id":1627115,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2024-02-22T22:30:52.000Z","date":"2024-02-20","kind":"grant","planned":false,"acquired":true,"shares":4284,"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 4,284 restricted stock units on the date of the grant. These shares are time-based restricted stock units that vest on the third anniversary of the grant date."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Included in this total are 3,773 shares held outright; 10,441 shares of Restricted Stock Units and 150,421 shares held with spouse."}],"balance_after":164635,"source":{"system":"sec-edgar","filing":"0001415889-24-004879","document":"form4-02222024_100227.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000141588924004879/form4-02222024_100227.xml","form_type":"4"}},{"id":1997665,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2023-02-23T19:18:31.000Z","date":"2023-02-21","kind":"grant","acquired":true,"shares":3077,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"These shares represent Restricted Stock Units granted 2-21-23 pursuant to the Old Second Bancorp, Inc. 2019 Equity Incentive Plan. These shares have a 3-year cliff vesting."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Included in this total are 1,500 shares held outright; 9,930 shares of Restricted Stock Units and 148,921 shares held with spouse."}],"balance_after":160351,"source":{"system":"sec-edgar","filing":"0001415889-23-003144","document":"form4-02232023_070220.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000141588923003144/form4-02232023_070220.xml","form_type":"4"}},{"id":2390435,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2022-02-17T19:37:16.000Z","date":"2022-02-15","kind":"grant","acquired":true,"shares":3080,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"These represent restricted stock units granted pursuant to the Old Second Bancorp, Inc. Long Term Incentive Plan. These shares have a three-year cliff vesting."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Included in this total are 147,421 shares held jointly with spouse and 9,853 shares of restricted stock units."}],"balance_after":157274,"source":{"system":"sec-edgar","filing":"0001415889-22-001499","document":"form4-02172022_110206.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000141588922001499/form4-02172022_110206.xml","form_type":"4"}},{"id":2578050,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2021-09-07T16:11:33.000Z","date":"2021-09-03","kind":"purchase","acquired":true,"shares":6835,"price":11.81,"value":80721.35,"ownership":{"direct":true},"footnotes":[{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F1","text":"Included in this total are 147,421 shares held jointly with spouse and 6,773 shares are restricted stock units held in Mr. McLean's name alone."}],"balance_after":154194,"source":{"system":"sec-edgar","filing":"0001179110-21-008632","document":"edgar.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/357173/000117911021008632/edgar.xml","form_type":"4"}},{"id":2578049,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2021-09-07T16:11:33.000Z","date":"2021-09-02","kind":"purchase","acquired":true,"shares":203,"price":11.85,"value":2405.55,"ownership":{"direct":true},"balance_after":147359,"source":{"system":"sec-edgar","filing":"0001179110-21-008632","document":"edgar.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/357173/000117911021008632/edgar.xml","form_type":"4"}},{"id":2578048,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2021-09-07T16:11:33.000Z","date":"2021-09-01","kind":"purchase","acquired":true,"shares":2962,"price":11.72,"value":34714.64,"ownership":{"direct":true},"balance_after":147156,"source":{"system":"sec-edgar","filing":"0001179110-21-008632","document":"edgar.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000117911021008632/edgar.xml","form_type":"4"}},{"id":2801921,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2021-03-09T22:51:42.000Z","date":"2021-03-08","kind":"tax_withholding","acquired":true,"shares":1579,"price":13.78,"value":21758.62,"ownership":{"direct":true},"footnotes":[{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F1","text":"Included in this total are 132,500 shares  held jointly with spouse, 6,773 shares are restricted stock units and 4,921shares are held in Mr. McLean's name alone."}],"balance_after":144194,"source":{"system":"sec-edgar","filing":"0001179110-21-003155","document":"edgar.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000117911021003155/edgar.xml","form_type":"4"}},{"id":2852595,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2021-02-18T23:52:01.000Z","date":"2021-02-16","kind":"grant","acquired":true,"shares":3773,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F2","text":"These shares represent Restricted Stock Units granted pursuant to the 2019 Long Term Equity Incentive Plan. These shares have a 3-year cliff vesting."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F1","text":"Included in this total are 130,000 shares  held jointly with spouse, 10,773 shares are restricted stock units and 5,000 shares are Performance Based restricted stock units in Mr. McLean's name alone."}],"balance_after":145773,"source":{"system":"sec-edgar","filing":"0001179110-21-001927","document":"edgar.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000117911021001927/edgar.xml","form_type":"4"}},{"id":3265363,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2020-02-19T20:12:12.000Z","date":"2020-02-18","kind":"grant","acquired":true,"shares":1500,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F3","text":"These shares represent Restricted Stock Units granted pursuant to the 2019 Long Term Equity Incentive Plan. These shares have a 3-year cliff vesting."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Does not apply."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F1","text":"Included in this total are 130,000 shares  held jointly with spouse, 7,000 shares are restricted stock units and 5,000 shares are Performance Based restricted stock units in Mr. McLean's name alone."}],"balance_after":142000,"source":{"system":"sec-edgar","filing":"0001179110-20-001809","document":"edgar.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000117911020001809/edgar.xml","form_type":"4"}},{"id":3445216,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2019-08-07T16:07:34.000Z","date":"2019-08-06","kind":"grant","acquired":true,"shares":5000,"price":11.968,"value":59840.0,"ownership":{"direct":true},"footnotes":[{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F1","text":"Included in this total are 130,000 shares  held jointly with spouse, 5,500 shares are restricted stock units and 5,000 shares are Performance Based restricted stock units in Mr. McLean's name alone."}],"balance_after":140500,"source":{"system":"sec-edgar","filing":"0001179110-19-009229","document":"edgar.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000117911019009229/edgar.xml","form_type":"4"}},{"id":3503679,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2019-06-04T16:33:22.000Z","date":"2019-06-03","kind":"grant","acquired":true,"shares":1500,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F3","text":"These shares represent Restricted Stock Units granted pursuant to the 2019 Long Term Equity Incentive Plan. These shares have a 3-year cliff vesting."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Does not apply."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F1","text":"Included in this total are 125,000 shares  held jointly with spouse, 5,500 shares are restricted stock units and 5,000 shares are Performance Based restricted stock units in Mr. McLean's name alone."}],"balance_after":135500,"source":{"system":"sec-edgar","filing":"0001179110-19-007084","document":"edgar.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000117911019007084/edgar.xml","form_type":"4"}},{"id":3961545,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2018-04-18T21:45:15.000Z","date":"2018-04-17","kind":"grant","acquired":true,"shares":5000,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F3","text":"These shares represent Performance Based Restricted Stock Units granted in 2018 under the Long Term Incentive Program. These shares have a 3-year cliff vesting."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Does not apply."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F1","text":"Included in this total are 125,000 shares  held jointly with spouse, 4,000 shares are restricted stock units and 5,000 shares are Performance Based restricted stock units in Mr. McLean's name alone."}],"balance_after":134000,"source":{"system":"sec-edgar","filing":"0001179110-18-005772","document":"edgar.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000117911018005772/edgar.xml","form_type":"4"}},{"id":4042300,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old Second Bancorp, Inc. Common Stock","published_at":"2018-02-22T17:02:30.000Z","date":"2018-02-20","kind":"grant","acquired":true,"shares":1500,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F3","text":"These shares represent Restricted Stock Units granted in 2018 under the Long Term Incentive Program. These shares have a 3-year cliff vesting."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Does not apply."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F1","text":"Of this total, 125,000 shares are held jointly with spouse and 4,000 shares are restricted stock units."}],"balance_after":129000,"source":{"system":"sec-edgar","filing":"0001179110-18-002570","document":"edgar.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000117911018002570/edgar.xml","form_type":"4"}},{"id":4433884,"issuer":{"id":2238,"kind":"organization","name":"OLD SECOND BANCORP INC","symbol":"OSBC"},"owners":[{"id":2265,"kind":"person","name":"MCLEAN HUGH H","position":1,"cik":"0001184764","reported_name":"MCLEAN HUGH H","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Old second Bancorp, Inc. Common Stock","published_at":"2017-02-22T22:48:30.000Z","date":"2017-02-21","kind":"grant","acquired":true,"shares":2500,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"These shares represent Restricted Stock Units granted in 2017 under Old Second's Equity Award Program. These shares have a 3-year cliff vesting."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Of this total, 125,000 shares are held jointly with spouse and 2,500 shares are restricted stock units."}],"balance_after":127500,"source":{"system":"sec-edgar","filing":"0001179110-17-002936","document":"edgar.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/357173/000117911017002936/edgar.xml","form_type":"4"}}]}