Government corporations, which first became a part of the executive branch during the World War I era, are sometimes set up to handle businesslike or commercial activities for the government. Prominent examples are the United States Postal Service, the Tennessee Valley Authority, and the Federal Deposit Insurance Corporation. Wholly owned by the government, they look pretty much like other government agencies, but they have greater operating flexibility in financial and personnel matters. Typically, they impose fees or charges for the goods or services that they provide and can reinvest earnings.