Cornerstone Bancorp Inc. operates as the bank holding company for Cornerstone National Bank & Trust Company that provides various financial products and services to individuals and businesses. It offers checking, savings, money market, and individual retirement accounts; and certificates of deposit. The company also provides home equity, vehicle, personal, equipment, association, and real estate construction loans; residential mortgages and refinances; construction, and medical and dental practice financing services; commercial and multi-family mortgages; and letters and lines of credit products. In addition, it provides online and mobile banking, payment, cash management, and bill pay services; and personal and business account services. Further, it offers securities custody accounts; investment management services; trust, estate, and retirement plans. Cornerstone Bancorp Inc. was founded in 2000 and is headquartered in Palatine, Illinois.