Old Second Bancorp, Inc. operates as the bank holding company for Old Second National Bank that provides community banking services in the United States. The company offers deposit products, including consumer and business checking, NOW, money market, savings, and other time deposit accounts, as well as certificates of deposit and individual retirement accounts. It also offers lending products, such as commercial and industrial loans; commercial real estate loans; multifamily loans; construction and development loans; residential real estate loans, such as residential first mortgage and second mortgage loans; home equity lines of credit; consumer loans, including motor vehicle, home improvement, and signature loans; installment and agricultural loans; lease financing receivables and overdraft checking; and safe deposit operations.