The secondary market agency reported late Tuesday that it acquired $42 billion in mortgages in November, down 14% from October.
In November 2012, Fannie purchased $99 billion in loans from its lenders.
Meanwhile, commitments to purchase new mortgages from lenders fell 14.5% from October to $47 billion in November—the lowest level in over two years.
Tuesday's report also shows Fannie's mortgage investment portfolio fell below $500 billion for the first time in over a decade. The GSE regulator has directed Fannie Mae and Freddie Mac to gradually reduce their giant portfolios.
Two years ago, Fannie had over $700 billion in mortgage assets in its investment portfolio.
The serious delinquency rate on Fannie's guaranteed single-family portfolio fell four basis points from October to 2.44% in November.