X0306 4 2021-12-31 0000357173 OLD SECOND BANCORP INC OSBC 0001673321 Pilmer Donald 37 S. RIVER ST. AURORA IL 60506 false true false false EVP Old Second Bancorp, Inc. Common Stock 2021-12-31 4 A 0 14 0 A 3048 I 401-K Plan Old Second Bancorp, Inc. Common Stock 2021-12-31 4 A 0 1 0 A 919 I Profit Sharing Plan Old Second Bancorp, Inc. Common Stock 1450 I Spouse's IRA Old Second Bancorp, Inc. Common Stock 64709 D Of this total, 14 shares were allocated during the fourth quarter pursuant to the Old Second Bancorp, Inc. Employee Savings Plan & Trust. Information herein was provided by the Plan Trustee as of 12-31-21. Of this total, 1 share was allocated during the fourth quarter pursuant to the Old Second Bancorp, Inc. Employees Profit Sharing Plan and Trust. Information herein was provided by the Plan Trustee as of 12-31-21. These shares are held in spouse's IRA for which Mr. Pilmer is listed as a beneficiary. Included in this total are 10 shares in Mr. Pilmer's name as custodian; 39,818 shares held in a brokerage account and 26,381 shares of Restricted Stock Units. /s/ Shirley Cantrell, Attorney-in-Fact 2021-12-31