Congress chartered Fannie Mae and Freddie Mac, also known collectively as the government-sponsored enterprises (GSEs), to promote homeownership for underserved groups and locations by providing liquidity to the secondary mortgage market. National mortgage rates tend to fall as the supply of funds in this market increases, making homeownership more affordable. This book describes Fannie Mae's and Freddie Mac's activities and mission and summarizes the progress made to date on FHFA's initiatives.