While serious delinquencies in the Fannie Mae (FNM) portfolio continue to reach new heights in January, mortgage-backed securitization (MBS) issuance dropped for the second month in a row in February, according to its monthly report. The serious delinquency rate at Fannie climbed to 5.52% in January – the most recent month of data – up 14 bps from December and doubling the 2.77% rate in January 2009. The single-family delinquency rate remains below the 4.03% rate in the portfolio of its brother Freddie Mac (FRE). Multi-family loans in the Fannie portfolio slipped into serious delinquency at a 0.69% rate in January, up from 0.63% in December. Fannie issued $43.9bn in mortgage-backed securities (MBS) in February, a 7% drop from the $47.6bn mark in January and a 2.8% decrease from the $45.2bn issued in February 2009. MBS issuances reached its peak in the last year in June 2009, when Fannie issued more than $130bn in MBS. Fannie’s book of business declined at an annualized rate of 1% in February. The gross mortgage portfolio also fell at an annualized rate of 14.2%. The new numbers came in a week after Timothy Geithner, secretary of the US Treasury Department, stressed the need of a process that would reform the GSE’s and remove “the umbrella of public protection” before Congress. Write to Jon Prior.