What Is Negative Amortization?
Quick Answers
Balance grows when
Payment less than interest
Risk
Owe more than borrowed
Neg-am cap typical
110-125% of original
Common in
Option ARMs (pre-2008)
Negative amortization occurs when your monthly loan payment is less than the interest due -- causing your loan balance to grow instead of shrink over time.
In a standard amortizing loan, each payment covers at least all the interest due and some principal, so your balance steadily decreases. With negative amortization, the payment is deliberately set below the full interest amount. The unpaid interest gets added to the loan principal -- meaning you owe more each month than you did the month before.
negative amortization was common in certain adjustable-rate mortgages and "option ARM" products before the 2008 financial crisis. They're now largely prohibited in qualified mortgages but still exist in some student loan income-driven repayment plans (where payments can fall below accruing interest).
Key Facts About Negative Amortization
- Balance grows: Instead of paying down debt, you're adding to it -- potentially ending up owing significantly more than you borrowed.
- Common in: Older option ARMs, certain student loan IDR plans, and some deferred-payment loans.
- Recast risk: Many neg-am loans have a recast point (typically when balance reaches 110125% of original loan) where payments jump dramatically to fully amortize the now-larger balance.
- Qualified mortgage rules: Under Dodd-Frank (2014), most residential mortgages cannot have negative amortization features.
- When it's unavoidable: Some income-driven student loan plans result in negative amortization for low-income borrowers -- interest accrues faster than payments cover it.
How Negative Amortization Works
Normal: Payment > Interest Due --> Balance decreases
Neg-Am: Payment < Interest Due --> Unpaid interest added to balance
Example: $200,000 loan, $900 interest due, $600 payment --> $300 added to balance monthly
That $300 monthly shortfall doesn't stay flat -- it compounds. Over just one year of making only the minimum payment, roughly $3,600 gets added to the $200,000 starting balance, and next year's interest is calculated on that larger amount, making the shortfall grow a little more each year until the loan hits its recast cap.
Common Negative Amortization Mistakes
- Treating the "minimum payment" option as a normal payment: On neg-am loans, the advertised low minimum payment is specifically the option that causes your balance to grow. Choosing a higher payment option on the same loan, when available, avoids the problem entirely.
- Assuming you have the full loan term before anything changes: The recast can trigger years early, as soon as the balance hits its cap (often 110-125% of the original loan). In a period of rising rates, the monthly interest shortfall gets larger, which can pull the recast date in sooner than borrowers expect.
Frequently Asked Questions
Is negative amortization always bad?+
For mortgages, it's almost always a bad outcome -- you're getting deeper into debt while making payments. For student loans on IDR plans, it can be intentional if you're pursuing loan forgiveness programs, where the growing balance may eventually be forgiven.
Can I have negative amortization on a fixed-rate loan?+
Standard fixed-rate loans are fully amortizing and cannot have negative amortization. Neg-am typically only occurs with certain variable-rate or minimum-payment structures.
What is a recast and when does it happen?+
A recast occurs when a neg-am loan hits a balance cap (usually 110125% of the original loan amount). At that point, the lender recalculates payments to fully amortize the larger balance over the remaining term -- often causing payments to spike dramatically.
How do I avoid negative amortization?+
Always make sure your monthly payment covers at least the full interest accruing on your loan. For student loans on IDR plans, making interest-only payments (even if the plan requires less) prevents balance growth.
Did negative amortization cause the 2008 housing crisis?+
It was one contributing factor. Many borrowers used option ARM loans that allowed minimum payments far below the accruing interest. When balances recast and payments jumped, many homeowners couldn't afford the new payments, leading to defaults.
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About the Author: De Van Do
De Van Do is the author and site builder behind MyLoanCalcs.com. With a background in technology, De Van Do built this site out of an interest in making financial calculations clear and accessible. De Van Do is not a licensed loan officer, mortgage broker, or financial advisor -- content on this site is for informational purposes only.