We do not believe that your institution will be liable for any forged checks that were not reported within the 30 days specified in your account agreement. Under the Uniform Commercial Code (UCC), a customer will be liable for any forged checks that are not reported with “reasonable promptness” (provided that the bank acted in good faith and exercised “ordinary care”). 810 ILCS 5/4-406(c), (e). Financial institutions may narrow the definition of “reasonable promptness” in account agreements, and an Illinois court has held that a 30-day notification window is permissible. 810 ILCS 5/4-103(a)Napleton v. Great Lakes Bank, N.A., 408 Ill.App.3d 448, 452 (1st Dist. 2011).