A conforming loan is a loan that meets bank funding criteria.
Because of its stake in the mortgage market and because of its history, Fannie Mae and Freddie Mac each year set the limit on what constitutes a conforming loan, based on the October-to-October changes in mean home price, above which a mortgage is considered a jumbo loan, and typically has higher rates associated with it. This is because both Fannie Mae and Freddie Mac only buy loans that are conforming, to repackage into the secondary market, making the demand for a non-conforming loan much less. By virtue of the laws of supply and demand, then, it is harder for lenders to sell the loans, thus it would cost more to the consumers (typically 1/4 to 1/2 of a percent.)
Limits for Alaska, Hawaii, Virgin Islands and Guam are 50% higher. Virgin Islands was designated a high cost area in 1992 and Guam in 2001.
Prior to 1984, second mortgage limits were the same as first mortgage limits. Subsequent legislation reduced the limits to 50% of first mortgage limits. Fannie Mae had no second mortgage program before 1981.
