Adjustable Rate Mortgages (ARMs) Boston MA

With a fixed-rate mortgage, the interest rate stays the same during the life of the loan. With an Adjustable Rate Mortgage (ARM), the interest rate changes periodically, usually in relation to an index, and payments may go up or down accordingly.

Adjustable Rate Mortgages

At-A-Glance

The Basic Features

The Adjustment Period: With most ARMs the adjustment period occurs every one, three or five years, resulting in a change in your interest rate and monthly payment.

The Index: Most lenders tie ARM interest rate changes to changes in an index rate. These indexes usually go up and down with the general movement of interest rates, making your monthly payment amount rise or fall accordingly.

The Margin: To determine the interest rate on an ARM, lenders add to the index rate a few percentage points called the margin. The amount of the margin can differ from one lender to another, but it is usually constant over the life of the loan.

This information is adapted from "Consumer Handbook on Adjustable Rate Mortgages" published by the Federal Reserve Board and the Office of Thrift Supervision.