An adjustable rate mortgage (ARM) has an interest rate that fluctuates periodically. This is in contrast to a fixed rate mortgage, which always has the same interest rate.
Every ARM has basic components:
- An index
- A margin
- Adjustment Period
- An interest rate cap
- An initial interest rate
An ARM’s interest rate is tied to one of many economic indices, some examples of which are the 1-year constant maturity Treasury security, the Cost of Funds Index, or the London Interbank Offered Rate. Different indices move at different rates so know the characteristics of the index used for your ARM.
The interest rate for your ARM will be calculated by adding a margin to the interest rate from the index. The margin is basically the markup charged by the lender that allows them to make a profit off of your loan, such as adding 2% to the index, where the 2% is the margin. The margin of your loan usually does not fluctuate.
The Adjustment Period
The Adjustment Period controls when and how often your interest rate changes. For example, if your ARM has an adjustment period of 1 year, your interest rate will be subject to change at the end of each year and your monthly mortgage payment will be recalculated to reflect this change.
The Interest Rate Cap
Interest rate caps are built into the loan to protect the borrower from drastic interest rate fluctuations. The caps limit how much the interest rate or monthly payment can change at the end of each adjustment period. An ARM can also have a cap for the life of the loan. For example, during the life of a loan, the interest rate can only be increased by 5%.
The Initial Interest Rate
The Initial Interest Rate is the interest rate that you start with at the beginning of your loan period. The length of time your loan stays at this rate is built into the loan. For example, you may stay at the initial interest rate for 1 year, 5 years, or another length of time depending on your specific mortgage. This type of ARM is generally referred to as a Hybrid ARM. The initial interest rate for an adjustable rate mortgage is generally lower than that of a fixed rate mortgage.
Now that you know what an ARM is and how it works, you may be wondering what the advantages and disadvantages are. So let’s explore that issue.
Offering adjustable rates allows lenders to transfer part of the interest rate risk from themselves to the borrower. If you get a fixed rate mortgage and the interest rate then goes up, it costs the lender money. However, if you have an adjustable rate mortgage, as the interest rate goes up, so does your payment, thus compensating the lender. Adjustable rate mortgages are particularly useful when unpredictable interest rates make fixed rate loans hard to get.
One of the main advantages of an adjustable rate mortgage is that the initial interest rate is lower than that of a fixed rate mortgage. A lower rate means lower payments, which may help you qualify for a larger loan. This is an important detail if you expect your future earnings to rise. In this case, the ARM will allow you to qualify for a larger loan amount earlier rather than later.
However, this information should only be used with care. If you use an ARM to qualify for a larger loan amount than a fixed rate would allow you and the interest rate then rises drastically or your income doesn’t rise, you may not be able to afford the larger monthly payments, thus causing you to default on your loan.
A situation in which an adjustable rate mortgage makes sense would be if you are only going to keep the house for a short period of time. If you are only planning to own your house for only a few years, the risk of the interest rate rising goes down. This means that you will get a better rate with an ARM, making it a good choice. However, if you plan on staying in your home for a long period of time, a fixed rate may be a better option.
The lesson here is to have a plan. Know what your goals are in purchasing a home and plan for all eventualities. Do your research when shopping for an ARM and consider the worst-case scenario.