Home builders PulteGroup and D.R. Horton Inc. each fell 9.1 percent. KB Home declined 6.6 percent; Beazer Homes USA fell 6.1 percent. The S&P Supercomposite Homebuilding index plunged 7.1 percent, the most in a year. The yield on the 10-year Treasury note rose to 2.43 percent Wednesday. Government bonds are benchmarks for mortgage rates; the sharp increase in yields prompted investors to sell stocks of builders, who could be hurt if home buying slows.