Fannie Mae mortgage portfolio continued to decline at an annual rate of 5.7% in June as the government-sponsored enterprise continued in its effort to reduce its role in the mortgage finance space.

The GSE's gross mortgage portfolio declined to $672.7 billion in June from $676.1 billion in May and $731.8 billion last year, according to a report from Fannie Mae.

The agency's total exposure to mortgage-backed securities and other guarantees hit $2.712 trillion in June, up slightly from $2.709 trillion in May and $2.701 trillion a year earlier.

Fannie had $201.9 billion in mortgage-backed securities within its portfolio in June, down from $231.5 billion a year ago.

The conventional single-family serious delinquency rate at Fannie Mae also fell four-basis points to 3.53% in June while the multifamily serious delinquency rate declined two-basis points to 0.29%.

Fannie completed 11,169 loan modifications during the month of June, bringing its total loan modification activity to 82,003 revamped loans in the first six months of 2012.