How to Shop For an Option ARM
18 July 2005, Revised October 20, 2006
"I want the low payments that are available on an option ARM, but I
don’t know what I should be looking for in shopping for one. Can you
help?"
Reluctantly. I don’t much like the option ARM because of its complexity
and hidden booby traps. However, some borrowers will ignore all warnings
because they are mesmerized by the low initial monthly payment,
calculated at rates as low as 1%. If you are going to take an option ARM
anyway, knowing their major features may save you some grief. Here they
are, in order of importance.
Margin: The Most Important Feature of an Option ARM
The option ARM adjusts the rate monthly. That means that the
lovely-looking 1% rate you saw in the ads holds for just one month. In
month 2 and every subsequent month, the rate is set to equal the most
recent value of the rate index plus a margin.
For example, assume your ARM uses MTA as the index and your margin is
3%. In May, 2005, MTA was 2.633%. If your first month with this loan was
May, in June your rate would jump from 1% to 5.633%.
The margin is fixed for the life of any one loan, but it varies widely
between borrowers. This makes it feature number one on your shopping
list. Further, if you don’t shop the margin, the chances are good you
won’t even know what it is until the loan closes. Loan providers usually
don’t volunteer it, and it is not a required disclosure.
Maximum Rate on an Option ARM
There are no rate adjustment caps on an option ARM. The only limit set
on the rate is a maximum over the life of the contract. This makes the
maximum rate feature number two on your shopping list. In today’s
market, look for a maximum of about 10%, but it can vary some from
lender to lender.
The tradeoff between margin and maximum rate is a judgment call, but I
would put it at about 2.5 to 1. If lender A offers a 3% margin and 10%
maximum, for example, and lender B wants a 4% margin, I would look for a
7.5% maximum from B to make the deals roughly equivalent.
Interest Rate Index
Most option ARMs use one of 4 indexes selected because of their relative
stability. These are called MTA, COFI, CODI and COSI.
There isn’t a lot of difference between these indexes. Over the last 12
years, COFI and COSI have averaged 4.0% while MTA and CODI have averaged
4.2%. (These figures come from www.mortgage-x.com, which is an excellent
source of information on ARM indexes). Hence, in comparing different
option ARMs, you can add .2% to the margin on an MTA or CODI ARM to make
them comparable to a COFI or COSI ARM.
Recast Period and Negative Amortization Cap
The great appeal of the option ARM is the low initial payment combined
with the 7.5% cap on annual payment increases. The payment in the early
years is not affected by interest rate changes, and in most cases does
not cover the interest. The result is a rising balance, or "negative
amortization".
However, a day of reckoning must come. Sooner or later, the payment must
become fully-amortizing -- large enough to pay off the balance over the
remaining term. This can happen smoothly by successive 7.5% annual
payment increases, or suddenly when the loan reaches the recast month or
hits a negative amortization cap.
On most option ARMs, the payment is recast every 5 years, though some
recast every 10 years. On the recast date, the payment becomes
fully-amortizing, no matter how large an increase that may require.
Option ARMs also have a limit on how large negative amortization can go,
ranging from 110% to 125% of the original loan amount. When the balance
hits the cap, the payment is immediately raised to the fully-amortizing
level, no matter how large an increase that may require.
All other things the same, a longer recast period and higher negative
amortization cap will delay a payment shock, and the shock will be
somewhat smaller when it occurs. For example, in one of many tests I ran
that are reported on my web site, the payment on an ARM with 5-year
recast rose by 7.5% for 4 years, and by 88% at recast. The same loan
with a 10-year recast rose by 7.5% for 9 years, and then by 61%.
The bottom line is that a longer recast and higher negative amortization
cap are desirable, but I would not accept a larger margin or higher
maximum rate to get them.
The Good News: Prices Don't Fluctuate
On all other mortgages, interest rates are reset every day. This means
that effective comparison shopping must be done within the day. On
option ARMs, in contrast, the principal price features do not vary with
the market. Hence, if need be you can stretch out your comparison
shopping without invalidating the results.