The Federal Reserve is currently buying $85 billion a month in bonds to keep interest rates low and to encourage spending and hiring. The housing market has benefited from low interest rates because they help make mortgages cheaper. After the Fed chairman said the bond purchases will continue, stocks of home builders like D.R. Horton (up 9.2 percent) rose. Lennar Corp. gained 8.3 percent, KB Home 7 percent, Pulte Group 7.2 percent, and Ryland Group 7 percent.