With the reduced demand for Fannie and Freddie mortgages with coupons under 5%, the Fed steps in and purchases $192 billion of 4% and 4.5% conforming mortgages on a gross basis by March 25, 2009. The move helps support falling house prices in the U.S. and reduces mortgage rates. It also helps banks improve profits. Estimates show the top 10 banks increased their holdings of securities issued by Fannie and Freddie and government agencies by $128.6 billion or 30% in 4th quarter 2008, which can be marked up in future quarters.