Mortgage Loan Types

There are many types of mortgage loans. The two basic types of amortized loans are the fixed rate mortgage (FRM) and adjustable rate mortgage (ARM).

In a FRM, the interest rate, and hence monthly payment, remains fixed for the life (or term) of the loan. In the U.S., the term is usually for 10, 15, 20, or 30 years. The only increase a consumer might see in their monthly payments would result from an increase in their property taxes or insurance rates (paid using an escrow account, if they've opted to use an escrow). But payments for principal and interest will be consistent throughout the life of the loan using an FRM.

In an ARM, the interest rate is fixed for a period of time, after which it will periodically (annually or monthly) adjust up or down to some market index. Common indices in the U.S. include the Prime Rate, the LIBOR, and the Treasury Index ("T-Bill"). Other indexes like 11th District Cost of Funds Index, COSI, and MTA, are also available but are less popular.

Adjustable rates transfer part of the interest rate risk from the lender to the borrower, and thus are widely used where unpredictable interest rates make fixed rate loans difficult to obtain. Since the risk is transferred, lenders will usually make the initial interest rate of the ARM's note anywhere from 0.5% to 2% lower than the average 30-year fixed rate.