Form 4 Filing for Jill E. York

This filing details transactions by Jill E. York, a director at Old Second Bancorp, Inc. The transactions primarily involve the acquisition of Old Second Bancorp, Inc. Common Stock through the automatic reinvestment of cash dividends. These acquisitions, occurring from May 11, 2021, to August 10, 2026, were due to an administrative oversight and are reported to correct the omission. The filing also notes that Ms. York beneficially owns 15,430 shares through her living trust as of October 15, 2026, superseding previously reported trust balances. Additionally, she holds 10,595 Restricted Stock Units. The reported transactions reflect shares acquired under dividend reinvestment features in her individual retirement account, with post-transaction holdings of 4319.6382 shares in this account for each reported transaction.