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How ARMs Work: The Basic Features
Initial rate and payment
The initial rate and payment amount on an ARM will remain in effect for a limited period—ranging from just 1 month to 5 years or more. For some ARMs, the initial rate and payment can vary greatly from the rates and payments later in the loan term. Even if interest rates are stable, your rates and payments could change a lot. If lenders or brokers quote the initial rate and payment on a loan, ask them for the annual percentage rate (APR). If the APR is significantly higher than the initial rate, then it is likely that your rate and payments will be a lot higher when the loan adjusts, even if general interest rates remain the same.
The adjustment period
With most ARMs, the interest rate and monthly payment change every month, quarter, year, 3 years, or 5 years. The period between rate changes is called the adjustment period. For example, a loan with an adjustment period of 1 year is called a 1-year ARM, and the interest rate and payment can change once every year; a loan with a 3-year adjustment period is called a 3-year ARM.
Loan Descriptions
Lenders must give you written information on each type of ARM loan you are interested in. The information must include the terms and conditions for each loan, including information about the index and margin, how your rate will be calculated, how often your rate can change, limits on changes (or caps), an example of how high your monthly payment might go, and other ARM features such as negative amortization.
The index
The interest rate on an ARM is made up of two parts: the index and the margin. The index is a measure of interest rates generally, and the margin is an extra amount that the lender adds. Your payments will be affected by any caps, or limits, on how high or low your rate can go. If the index rate moves up, so does your interest rate in most circumstances, and you will probably have to make higher monthly payments. On the other hand, if the index rate goes down, your monthly payment could go down. Not all ARMs adjust downward, however—be sure to read the information for the loan you are considering.
Lenders base ARM rates on a variety of indexes. Among the most common indexes are the rates on 1-year constant-maturity Treasury (CMT) securities, the Cost of Funds Index (COFI), and the London Interbank Offered Rate (LIBOR). A few lenders use their own cost of funds as an index, rather than using other indexes. You should ask what index will be used, how it has fluctuated in the past, and where it is published—you can find a lot of this information in major newspapers and on the Internet.
To help you get an idea of how to compare different indexes, the following chart shows a few common indexes over an 11-year period (1996–2008). As you can see, some index rates tend to be higher than others, and some change more often. But if a lender bases interest-rate adjustments on the average value of an index over time, your interest rate would not change as dramatically.
The margin
To set the interest rate on an ARM, lenders add a few percentage points to the index rate, called the margin. The amount of the margin may differ from one lender to another, but it is usually constant over the life of the loan. The fully indexed rate is equal to the margin plus the index. If the initial rate on the loan is less than the fully indexed rate, it is called a discounted index rate. For example, if the lender uses an index that currently is 4% and adds a 3% margin, the fully indexed rate would be
If the index on this loan rose to 5%, the fully indexed rate would be 8% (5% + 3%). If the index fell to 2%, the fully indexed rate would be 5% (2% + 3%).
Some lenders base the amount of the margin on your credit record—the better your credit, the lower the margin they add—and the lower the interest you will have to pay on your mortgage. In comparing ARMs, look at both the index and margin for each program.
No-Doc/Low-Doc Loans
When you apply for a loan, lenders usually require documents to prove that your income is high enough to repay the loan. For example, a lender might ask to see copies of your most recent pay stubs, income tax filings, and bank account statements. In a “no-doc” or “low-doc” loan, the lender doesn’t require you to bring proof of your income, but you will usually have to pay a higher interest rate or extra fees to get the loan. Lenders generally charge more for no-doc/low-doc loans.
Interest-rate caps
An interest-rate cap places a limit on the amount your interest rate can increase. Interest caps come in two versions:
- periodic adjustment cap, which limits the amount the interest rate can adjust up or down from one adjustment period to the next after the first adjustment, and
- lifetime cap, which limits the interest-rate increase over the life of the loan. By law, virtually all ARMs must have a lifetime cap.
Periodic adjustment caps
Let’s suppose you have an ARM with a periodic adjustment interest-rate cap of 2%. However, at the first adjustment, the index rate has risen 3%. The following example shows what happens.
Examples in This Handbook
All examples in this handbook are based on a $200,000 loan amount and a 30-year term. Payment amounts in the examples do not include taxes, insurance, condominium or homeowner association fees, or similar items. These amounts can be a significant part of your monthly payment.
In this example, because of the cap on your loan, your monthly payment in year 2 is $138.70 per month lower than it would be without the cap, saving you $1,664.40 over the year.
Some ARMs allow a larger rate change at the first adjustment and then apply a periodic adjustment cap to all future adjustments.
A drop in interest rates does not always lead to a drop in your monthly payments. With some ARMs that have interest-rate caps, the cap may hold your rate and payment below what it would have been if the change in the index rate had been fully applied. The increase in the interest that was not imposed because of the rate cap might carry over to future rate adjustments. This is called carryover. So, at the next adjustment date, your payment might increase even though the index rate has stayed the same or declined.
The following example shows how carryovers work. Suppose the index on your ARM increased 3% during the first year. Because this ARM limits rate increases to 2% at any one time, the rate is adjusted by only 2%, to 8% for the second year. However, the remaining 1% increase in the index carries over to the next time the lender can adjust rates. So, when the lender adjusts the interest rate for the third year, even if there has been no change in the index during the second year, the rate still increases by 1%, to 9%.
In general, the rate on your loan can go up at any scheduled adjustment date when the lender’s standard ARM rate (the index plus the margin) is higher than the rate you are paying before
that adjustment.
Lifetime caps
The next example shows how a lifetime rate cap would affect your loan. Let’s say that your ARM starts out with a 6% rate and the loan has a 6% lifetime cap—that is, the rate can never exceed 12%. Suppose the index rate increases 1% in each of the next 9 years. With a 6% overall cap, your payment would never exceed $1,998.84—compared with the $2,409.11 that it would have reached in the tenth year without a cap.
Payment caps
In addition to interest-rate caps, many ARMs—including payment-option ARMs (discussed on page 16)—limit, or cap, the amount your monthly payment may increase at the time of each adjustment. For example, if your loan has a payment cap of 7½%, your monthly payment won’t increase more than 7½% over your previous payment, even if interest rates rise more. For example, if your monthly payment in year 1 of your mortgage was $1,000, it could only go up to $1,075 in year 2 (7½% of $1,000 is an additional $75). Any interest you don’t pay because of the payment cap will be added to the balance of your loan. A payment cap can limit the increase to your monthly payments but also can add to the amount you owe on the loan. (This is called negative amortization, a term explained on page 22.)
Let’s assume that your rate changes in the first year by 2 percentage points, but your payments can increase no more than 7½% in any 1 year. The following graph shows what your monthly
payments would look like.
While your monthly payment will be only $1,289.03 for the second year, the difference of $172.69 each month will be added to the balance of your loan and will lead to negative amortization.
Some ARMs with payment caps do not have periodic interestrate caps. In addition, as explained below, most payment-option ARMs have a built-in recalculation period, usually every 5 years. At that point, your payment will be recalculated (lenders use the term recast) based on the remaining term of the loan. If you have a 30-year loan and you are at the end of year 5, your payment will be recalculated for the remaining 25 years. The payment cap does not apply to this adjustment. If your loan balance has increased, or if interest rates have risen faster than your payments, your payments could go up a lot.
Types of ARMs >