What is the margin on an ARM?

The margin is the fixed percentage that a lender adds to the ARM's index rate at each adjustment period to arrive at your new interest rate. While the index fluctuates based on market conditions, the margin is set at the time the loan is originated and does not change over the life of the loan. Your interest rate at any adjustment period equals the current index plus the margin.

When comparing ARM products, the margin is one of the most important factors to evaluate — a lower margin means a lower rate at every adjustment, regardless of where the index stands. Lenders may offer varying margins even on loans tied to the same index, so it pays to ask specifically about the margin when shopping for an ARM. For buyers in the Western Catskills considering ARM financing for a second home or seasonal property in Delaware, Ulster, Greene, or Otsego counties, understanding the margin helps clarify the realistic range of future payments.