Federal National Mortgage Association is engaged in providing a source of financing for residential mortgages in the United States. It is a government-sponsored, stockholder-owned corporation, chartered by Congress to provide liquidity and stability to the United States housing market and to promote access to mortgage credit. Its segments include Single-Family and Multifamily. The Single-Family business operates in the secondary mortgage market relating to loans secured by properties containing four or fewer residential dwelling units. The Multifamily business operates in the secondary mortgage market relating to loans secured by properties containing five or more residential units. Its categories of mortgage securitization transactions include lender swap transactions, portfolio securitization transactions, and structured securitization transactions. It funds its business through the issuance of short and long-term debt securities in the domestic and international capital markets.