Fannie Mae and Freddie Mac can begin buying single-family mortgages of up to $417,000 in January of 2006, in what amounts to the biggest annual increase ever in the so-called conforming loan limit. The top single-family loan eligible for sale to the government-sponsored enterprise this year is $359,650, with various adjustments for multi-dwelling loans and mortgages in U.S. territory outside the lower 48 states. The 16.0 percent jump to $417,000, based on an otherwise obscure… [One data table included]