On May 25, 2023, Old Second Bancorp, Inc. notified Wells Fargo National Bank, National Association, as trustee and paying agent, of its intention to redeem (the Redemption") on June 30, 2023 (the Redemption Date") all of its outstanding 5.750% Fixed-to-Floating Rate Senior Notes due 2026 (CUSIP No. 680277 AB6), originally issued on December 15, 2016 (the Senior Notes"), at a cash redemption price (the Redemption Price") to be calculated as provided in the Senior Notes, equal to 100% of the $45,000,000 aggregate principal amount of the Senior Notes, plus the accrued and unpaid interest thereon through, but excluding, the Redemption Date. Upon completion of the Redemption, no Senior Notes will remain outstanding.

Payment of the Redemption Price will be made on the Redemption Date only upon presentation and surrender of the Senior Notes to the Trustee in its capacity as Paying Agent. Senior Notes held in book-entry form will be redeemed and the Redemption Price with respect to such Senior Notes will be paid in accordance with the applicable procedures of the Depository Trust Company. Interest on the Senior Notes called for redemption will cease to accrue on and after the Redemption Date.

Notice of redemption will be sent to the registered holders of the Senior Notes.