ARM: What They Don't Tell You
The details about adjustable-rate mortgages that often get left out of the pitch.
What Is an ARM, Really?
An adjustable-rate mortgage (ARM) has a rate that's fixed for an initial period, commonly 5, 7, or 10 years, and then adjusts periodically for the rest of the loan term based on a market index (currently SOFR for most ARMs) plus a fixed margin set at closing. The loan term is still 30 years total, so once the fixed period ends, you still have 20 to 25 years of potential rate adjustments ahead, not a fresh start.
What Often Gets Left Out of the Pitch
- Your rate can adjust a lot, even with caps. Caps limit how much your rate can change at once, but they don't cap it at zero. Common structures like 2/1/5 or 5/1/5 still allow your rate to rise several percentage points over the life of the loan.
- Your first adjustment isn't the only one. Modern ARMs (5/6, 7/6, 10/6) adjust every six months after the fixed period ends, not just once a year or one time only.
- The margin never changes, but the index can move a lot. Your rate is the index plus your margin, and while the margin is locked in at closing, the index isn't, so your future rate depends on market conditions no one can predict today.
- You may need to qualify based on more than just your start rate. Depending on the loan, you may need to show you could handle a higher payment than your introductory one, not just the lower initial payment.
- "Lower initial payment" doesn't mean lower total cost. If rates rise before you sell or refinance, your total interest paid over time can end up higher than a comparable fixed-rate loan.
A Real Example
On a 7/6 ARM starting at a 5.75% rate with a 5/1/5 cap structure, the rate could rise as much as 5 percentage points at the very first adjustment alone. Depending on your loan amount, that can mean hundreds of dollars more in your monthly payment practically overnight.
When an ARM Can Still Make Sense
- You're confident you'll sell or refinance before the fixed period ends
- The rate gap between the ARM and a fixed-rate loan is large enough to make the lower initial payment worth the risk
- You can comfortably afford the worst-case payment, not just the starting one
Is an ARM Right for You?
Here at Efinity Mortgage, we walk through your specific ARM's caps, margin, and worst-case payment scenario with you, not just the introductory rate, so you know exactly what you're signing up for before you commit.
Common Questions
Does my ARM rate reset just once?
No. Most modern ARMs (5/6, 7/6, 10/6) adjust every six months after the initial fixed period ends, not just one time.
Can my rate go down instead of up?
Yes. Your rate is tied to a market index, so if that index falls, your rate can decrease at your next adjustment, subject to any rate floor in your loan.
What stops my rate from going sky-high?
Rate caps, specifically an initial cap, a periodic cap, and a lifetime cap, limit how much your rate can change at once and over the life of the loan, though they don't eliminate risk entirely.
Do I need to qualify for the higher future payment?
In many cases, yes. Depending on the loan, you may need to demonstrate you could afford a payment higher than your introductory one, not just the lower starting payment.