Old Second Bancorp, Inc. is the holding company of Old Second National Bank, a national banking organization headquartered in Aurora, Illinois that provides commercial and retail banking services, as well as a full complement of trust and wealth management services. Old Second serves retail, commercial, industrial, and public-entity customers throughout the greater Chicago area via its offices in Cook, Kane, Kendall, DeKalb, DuPage, LaSalle and Will counties in Illinois.