Freddie Mac engages in mortgage purchasing, credit guarantee, and portfolio investment activities in the United States. It purchases single family and multi-family residential mortgages, and mortgage-related securities from lenders in the primary mortgage market that originate mortgages for homebuyers, including mortgage banking companies, commercial banks, savings banks, community banks, credit unions, state and local housing finance agencies, and savings and loan associations. The company also buys mortgage whole loans and mortgage-related securities, and issues guaranteed mortgage-related securities in the secondary market. In addition, it purchases non-securitized mortgage loans and mortgage-related securities for its investments portfolio. Further, Freddie Mac guarantees the payment of principal and interest on mortgage-related securities, including single-class and multi-class structured securities, mortgage participation certificates issued by the company, and securities related to tax-exempt multifamily housing revenue bonds. The company was founded in 1970 and is headquartered in McLean, Virginia.