The Government National Mortgage Association -- or Ginnie Mae -- posted $38.98bn in mortgage-backed securities issuance in May, bringing the 2009 total so far to $163bn, more than double the nearly $80bn seen in the first five months of 2008. "Our MBS program is continuing to experience phenomenal growth," said president Joseph Murin in a statement this week. "Clearly, as the economy continues to find its footing, there is still a strong need for a safe, dependable security like the Ginnie Mae MBS." Multifamily MBS issuance accounted for $319m of the month's total, while the rest consisted of single-family issuance. By taking loan pools and securitizing on the secondary market, Ginnie provides liquidity for mortgage lenders and, in turn, small mortgage bankers that sell loans to big lenders. With the full faith and credit of the US government, Ginnie is in the position of taking on loans guaranteed by the Federal Housing Administration, the Department of Veteran Affairs, the Department of Agriculture's Rural Development and Department of Housing, as well as the US Department of Housing and Urban Development's Office of Public and Indian Housing. Ginnie also participates in the Federal Reserve's MBS purchase program as an ongoing part of the Fed’s role in the so-called “dollar roll” market — a purchase agreement where the seller traditionally sells the security now under an agreement to buy it back in the future at a lower price. The Fed purchased $3.65bn of MBS from Ginnie in the most recent week of transactions, providing a bit of liquidity for other issuance. Write to Diana Golobay.