Fannie Mae, the US government-supported mortgage-finance company, sold $7bn of three- year notes, in the largest sale of its benchmark securities since March 2009. The debt yields 1.057%, or 23.5 basis points more than similar-maturity Treasuries, the Washington-based company said today in a statement. On July 8, Fannie Mae sold $6bn of its three-year benchmark notes at the same spread and a yield of 1.257%