The serious delinquency rate at government-sponsored enterprise (GSE) Fannie Mae ($0.00 0%) rose nine basis points (bps) to 5.38% in the single-family mortgage book. Its a slight increase from 5.29% last month.

The serious delinquency rate for multi-family loans slipped three bps to 0.63%, according to the January monthly volume summary (download here).

Fannie's serious delinquency rate compares with 4.03% of fellow GSE Freddie Mac's ($0.00 0%) single-family loans in January.

Fannie's book of business declined at a compound annualized rate of 5% in January, while the gross mortgage portfolio shrank at a compound annualized rate of 44.8%.

Total Fannie mortgage-backed securities (MBS) issuances in January were$47.6bn, down from $55.4bn in December.

The news comes after Fannie said this week it expects to purchase from 150,000 to 200,000 delinquent loans out of single-family MBS trusts during March.

This month will mark only the beginning of Fannie’s plan to buyout loans 120+ days delinquent. The GSE said in a press statement it expects to continue purchasing delinquent loans in subsequent months until the seriously delinquent loan population is “substantially reduced.”

Fannie requested $15.3bn of aid from the Treasury Department last week after posting a $15.2bn net loss for Q409.

Write to Diana Golobay.

Disclosure: The author holds no relevant investment positons.