How to Qualify for an Interest-Only Mortgage: Credit and Income

To qualify for an interest-only mortgage, you generally need a credit score of at least 700, a down payment of 20% or more, cash reserves covering several months of payments after closing, and income strong enough to support the fully amortized payment rather than the lower interest-only one. These loans sit outside the federal “qualified mortgage” category, so fewer lenders offer them, and the ones that do apply tighter standards than they would to a conventional loan.¹

Credit Score and Credit History

Most lenders set the floor at a FICO score of 700, with 720 required for competitive pricing and 740 or higher for the best terms. That’s meaningfully stricter than what a conventional or government-backed mortgage would ask for, and it reflects the added risk of a loan whose balance doesn’t shrink during the initial years.

Past derogatory events create waiting periods. Fannie Mae’s conventional-loan framework, which most lenders track closely, requires four years after a Chapter 7 or Chapter 11 bankruptcy discharge or dismissal, two years after a Chapter 13 discharge (four from a dismissal), seven years after a completed foreclosure, and four years after a short sale or deed-in-lieu.² Non-QM lenders may use different timelines and sometimes consider borrowers earlier with documented extenuating circumstances. Outstanding judgments or tax liens almost always have to be cleared before closing, and you should expect to write letters of explanation for anything negative on your report.

Down Payment and Equity

A 20% down payment is the baseline. Depending on the loan amount, the property type, and your overall profile, many lenders push that to 25% or 30%. This equity cushion protects the lender against a decline in property value, since your principal balance won’t be dropping during the interest-only phase.

The same logic governs refinances through loan-to-value limits. Most lenders cap LTV at 80% for an interest-only refinance, meaning at least 20% equity in the property. Some programs tighten that to 70% LTV for cash-out refinances or investment properties. A professional appraisal confirms the current market value and whether you meet the threshold.

Investment properties face stricter standards still, with higher down payment and reserve demands. Condominiums bring their own hurdles: most lenders require the project to meet eligibility standards covering commercial-space limits, single-entity ownership concentration, and active HOA litigation.

Income and Debt-to-Income Ratio

Because interest-only loans aren’t qualified mortgages, lenders aren’t bound by the 43% DTI ceiling that historically defined that category.³ Non-QM programs commonly allow DTI up to 50%, and sometimes higher when a large down payment or strong liquid assets offset the risk.

Here’s the part that trips people up. The lender will not qualify you at the interest-only payment. Federal law under 15 U.S.C. 1639c requires a reasonable, good-faith determination of your ability to repay based on verified documentation, using a fully amortizing payment schedule over the loan’s full term.⁴ For an adjustable-rate interest-only loan, CFPB guidance directs lenders to use the greater of the fully indexed rate or the introductory rate when calculating that amortizing payment.¹

An example makes the math concrete. On a $400,000 loan at 7% with a 10-year interest-only period on a 30-year term, the interest-only payment runs about $2,333 a month. The lender qualifies you against roughly $3,100 a month, which is what it would take to amortize the full balance over the remaining 20 years. Your DTI is calculated against that higher figure, with all your other monthly debts folded in. The statute also requires the lender to weigh credit history, current and expected income, employment status, existing debts, and financial resources beyond the home’s equity.⁴

Cash Reserves After Closing

Lenders want proof you can keep paying if your income dips. Reserve requirements scale with the loan size. A common non-QM structure asks for three months of reserves on loans up to $1 million, six months on loans between $1 million and $2 million, and twelve months on anything above $2 million. Reserves are measured against the full monthly housing payment: principal, interest, taxes, insurance, and any association dues.

Acceptable reserves include checking, savings, money market funds, and brokerage accounts that can be liquidated readily. Retirement accounts like 401(k)s and IRAs sometimes count, though lenders may discount their value to account for early-withdrawal penalties. Whatever you claim has to be documented with recent statements, and the funds have to remain after your down payment and closing costs are paid.

Documents You’ll Need

Start collecting these early. Underwriting on a non-QM loan is document-heavy, and inconsistencies between your application and your paperwork will trigger follow-up requests that slow the file down.

Two years of federal tax returns with all schedules, plus matching W-2s or 1099s. Self-employed borrowers should expect to add profit-and-loss statements and business returns.
Two to three consecutive months of statements for every personal and business account, with written explanations for any large or irregular deposits.
Recent statements for retirement, brokerage, and any other accounts you’re using to meet reserve requirements.
Government-issued photo ID and Social Security numbers for everyone on the loan.
Proof of hazard insurance on the property, at coverage based on either the replacement cost or the unpaid loan balance, whichever produces the applicable minimum under the lender’s guidelines.⁵

The application itself is the Uniform Residential Loan Application, Form 1003, which nearly every mortgage lender uses regardless of where the loan ends up.⁶ It captures your income, monthly debts, assets, and employment history in a standard format.

Where to Find a Lender

Because interest-only loans are excluded from the qualified mortgage category, they can’t be sold to Fannie Mae or Freddie Mac through the standard programs.³ Lenders that offer them either hold the loans in their own portfolios or sell them on the private secondary market. In practice, that means large banks, credit unions, and specialty non-QM lenders. Many interest-only mortgages are structured as jumbo loans for higher-priced properties, though some lenders write them at lower loan amounts as well.

Plan for the Payment Jump

Qualifying for the loan is one thing; carrying it through the recast is another, and lenders will size you up for both. When the interest-only period ends, your entire principal balance has to be repaid over whatever time remains on the loan. Since none of it has come down during the interest-only years, the payment increase is steep.

On the $400,000 example above, the monthly payment climbs from roughly $2,333 to about $3,100 the month the recast hits. That’s a 33% jump with no change in your income. On a larger loan, or on an adjustable-rate product where the index has moved up, the increase can be sharper. Some borrowers plan to sell or refinance before the recast, but that plan depends on property values and rates cooperating. If they don’t, you’re locked into the higher payment. Running your budget against that fully amortized figure before you apply is the honest test of whether you qualify in any meaningful sense, and it’s the same test the lender is required to apply.

1
Consumer Financial Protection Bureau. Ability-to-Repay and Qualified Mortgage Rule
2
Fannie Mae. Significant Derogatory Credit Events – Waiting Periods and Re-establishing Credit
3
Federal Register. Qualified Mortgage Definition Under the Truth in Lending Act (Regulation Z)
4
GovInfo. 15 USC 1639c – Minimum Standards for Residential Mortgage Loans
5
Fannie Mae. Joint FAQs Related to the Perspectives Blog – Keeping What Works
6
Fannie Mae. Uniform Residential Loan Application (Form 1003)