The central bank bought a gross amount of $7.95 billion in mortgage securities guaranteed by Fannie Mae, Freddie Mac and the Government National Mortgage Association (Ginnie Mae) in the latest week.

During this period, it sold only $400 million of agency mortgage bonds from its portfolio, down from $4.35 billion in the prior week, the New York Fed said on its website.

Since the start of October, the Fed began to reinvest the principal payments from its agency debt and agency MBS in agency MBS in an effort to hold down mortgage rates and support the US housing market.