Several adjustable rate mortgages, or ARMs, are available to homeowners and they include 6-Month Certificate of Deposit ARM, 1-Year Treasury Spot ARM, 6-Month Treasury Average ARM, and the 12-Month Treasury Average ARM. An ARM that reacts quickly to the market will allow the borrower to benefit from falling interest rates. An ARM that lags behind the market will allow the borrower to take advantage of lower rates when rates begin to increase. As a borrower, it is important to watch the market and speak with your mortgage broker to decide which type of ARM will best fit your home loan needs