Fannie Mae operates a massive, highly profitable secondary mortgage market securitization and credit guaranty business model divided into two principal reporting segments: (1) Single-Family Business (~88% of net revenue), which purchases conventional conforming single-family residential mortgages from primary lenders, securitizes them into Uniform Mortgage-Backed Securities (UMBS), and guarantees the timely payment of principal and interest to institutional investors worldwide in exchange for a recurring guaranty fee (typically averaging 45 to 55 basis points on the unpaid principal balance); and (2) Multifamily Business (~12% of net revenue), which finances affordable and market-rate apartment communities through its Delegated Underwriting and Servicing (DUS) lender network, sharing credit loss risk with approved commercial lenders. Crucially, Fannie Mae does not make money by speculating on home price appreciation or holding massive unhedged loan portfolios; instead, it acts as a credit guarantor, earning steady, recurring guaranty fees across its $4.1 trillion portfolio while transferring credit risk to private capital through its benchmark Connecticut Avenue Securities (CAS) credit risk transfer (CRT) programs.