Federal National Mortgage Association Fannie Mae

Fannie Mae buys mortgages from lenders (banks, credit unions, mortgage companies), packages them into mortgage-backed securities (MBS), and sells those securities to investors — keeping the U.S. housing market liquid.

It operates in two segments: Single-Family (loans on 1–4 unit homes, the dominant revenue source) and Multifamily (loans on apartment buildings and other 5+ unit properties).

Revenue comes primarily from guarantee fees charged to MBS investors in exchange for bearing credit risk on the underlying loans. Customers are mortgage lenders on the origination side and institutional investors on the securities side. Fannie Mae is a government-sponsored enterprise (GSE) operating under federal conservatorship since 2008.