In the United States, a commercial bank is defined by the U.S. Code (12 U.S.C.A. § 1841 (c)(1) ). It is a financial corporation organized under U.S. law or the laws of any state, the District of Columbia, any territory of the United States, Puerto Rico, Guam, American Samoa, or the Virgin Islands. It must accept demand deposits which the depositor can withdraw at any time (upon demand) usually through writing a check. It may also engage in the business of using deposits for commercial loans. There are laws governing the ratio of loans to deposits.