The volume of commercial and multifamily mortgage debt outstanding remained largely unchanged throughout the first quarter of 2009 at $3.48trn. Multifamily mortgage debt outstanding grew 0.6% from Q408 to $908bn in Q109, according to data analyzed by the Mortgage Bankers Association. Government-sponsored enterprises and mortgage giants Freddie Mac (FRE) and Fannie Mae (FNM) hold the largest chunk of outstanding multifamily, with $191bn in federally-regulated mortgage pools and $154bn in their own portfolios. "Banks, thrifts, Fannie Mae and Freddie Mac all increased their holdings of commercial and multifamily mortgages during the first quarter, while run-off among CMBS and life company loans decreased those investors' holdings," said Jamie Woodwell, MBA's vice president of Commercial Real Estate Research, in a media statement. "The relatively long-term nature of commercial real estate finance," Woodwell adds, "has meant greater stability in the levels of commercial and multifamily mortgage debt outstanding than is seen among many other types of credit." Commercial banks hold the largest chunk -- $1.56trn or 45% -- of commercial and multifamily mortgages, while issuers of commercial mortgage-backed securities (CMBS) and other asset-backed securities hold the second-largest chunk -- $763bn or 21%, according to the MBA's findings. Between Q408 and Q109, the number of loans at least 30 days delinquent held in CMBS rose 0.68 percentage points to 1.85%, according to the MBA’s Commerical/Multifamily Delinquency Report. The delinquencies must have continued in the months since, as one ratings agency noted an alarming rate as recently as May. Fitch Ratings this week warned on rising delinquencies among CMBS as the retail and multifamily loans collateralizing them continue to perform poorly and ultimately default. CMBS experienced a 2.07% delinquency rate in May, the highest ever recorded by the ratings agency since beginning its loan delinquency index in 2001. “Defaults on larger loans continue to drive delinquency increases because later vintage transactions have larger loans, many underwritten with now unrealized proforma income, as well as now-depleted debt service reserves and high leverage,” says  US CMBS group head Susan Merrick in a media statement. Write to Diana Golobay. For an in-depth look at CMBS, please see the July 2009 issue of HousingWire magazine. Disclosure: The author held no relevant investment positions when this story was published. Indirect holdings may exist via mutual fund investments.