Is This Interest-Only ARM a N0-Brainer?
February 18, 2003, Revised November 18, 2006
"I plan to refinance my 7.25% loan into a 4% adjustable rate mortgage
(ARM) that is interest-only for 10 years. I don’t plan to hold this
mortgage for more than 8 years. Unless I’m missing something, the
decision seems like a no-brainer."
You are missing something. The fact that this ARM is interest-only for
10 years does not mean that the 4% rate holds for 10 years. Probably it
holds for only 6 months. Then, it can spike, or maybe not, depending on
what happens to market interest rates during the period, and on other
features of this loan that you don’t know about. This risk makes your
decision anything but a "no-brainer".
Interest-Only Period Versus Initial Rate Period
Your letter is one of many I have received recently that ask about
10-year interest-only ARMs. It took me awhile to realize what was going
on. Some smart operators are taking advantage of the recent popularity
of interest-only loans to confuse borrowers into believing that the
tooth fairy has arrived. Only the tooth fairy is offering mortgages at
4% for 10 years.
These smart alecks don’t lie, but they allow prospective borrowers to
lie to themselves. Borrowers are left to assume that the interest-only
period is the same as the initial rate period. It is not. The
interest-only period is the period during which you are allowed to pay
interest only. The initial rate period is the period for which the
quoted interest rate holds.
To illustrate the difference, assume the initial rate period is 6 months
and the interest only period 10 years. On a $100,000 loan at 4%, the
interest-only payment is $333. If the rate after 6 months goes to 6%,
the interest-only payment would jump to $500. It is higher because the
interest rate is higher, but it remains interest-only.
How fast and how far a rate increase might go depends partly on what
happens in the market. There is no way to know that. But it also depends
on the contractual features of this ARM, which you can know but haven’t
yet bothered to find out.
Information Needed For Determining the "Worst Case"
To find out at least how bad it could be – the "worst case" – you need
to know the following:
* How long the initial rate holds -- assume 6 months.
* How often the rate adjusts after the initial rate period ends --
assume every 3 months.
* The maximum rate change -- assume 2% on the first adjustment, 1% on
subsequent adjustments.
* The highest rate allowed by the contract -- assume 10%.
Using the assumptions I made above, under a worst case the rate would
rise from 4% to 10% in 18 months. On a $100,000 loan, the initial
payment of $333.34 would jump to $500 in month 7, to $583.34 in month
10, to $666.67 in month 13, to $750 in month 16, and to $833.34 in month
19.
An Overlooked Hazard in Interest-Only Loans
This example points up a hazard in an interest-only ARM that loan
officers are not likely to raise. The payment increase resulting from an
interest rate increase is significantly larger than on an ARM that
requires a fully-amortizing payment. A fully amortizing payment includes
principal and will pay off the balance at term. The payment on a
fully-amortizing ARM would begin at $477.42 and rise to $868.85 in month
19. This is an 82% increase, compared to a 150% increase in the
interest-only payment.
This does not mean that the ARM under discussion is a bad instrument
that should be avoided. The point is that ARMs should be selected with
eyes wide open to their risk. It is the difference between selecting an
ARM and being sold an ARM.
Unfortunately, loan providers seldom volunteer the information needed to
assess the risk – you have to ask for it. There is a checklist on my web
site you can use for this purpose – see Information Needed to Evaluate
an ARM. If the loan officer can’t or won’t fill it in, run.