What Happens If You Underestimate Income for ACA? The Repayment Rules

If you underestimate your income and receive more advance premium tax credit (APTC) than you qualify for, you must repay the excess when you file your tax return using Form 8962. For tax year 2027coverage, there is an especially important wrinkle: the One Big Beautiful Budget Act (OBBBA) eliminated the income-based repayment caps that previously limited how much lower-income households had to pay back. Under current law, the full excess APTC is owed with no cap. Use our ACA subsidy calculator to estimate your credit accurately and avoid surprises.

How APTC reconciliation works

When you enroll in marketplace coverage, you estimate your expected household income for the year. The marketplace uses that estimate to calculate your advance premium tax credit, which it pays directly to your insurer each month to lower your premium bill.

At the end of the year, when you file your tax return, the IRS compares:

1. The APTC you actually received: The total advance credits paid to your insurer during the year, reported on Form 1095-A from your marketplace.
2. The premium tax credit you actually qualify for: Calculated on Form 8962 using your actual household income for the year.

If the credit you qualify for is greater than what was paid in advance, you receive the difference as an additional refund or reduction in taxes owed. If the advance payments exceed what you qualify for, you must repay the excess.

Form 8962: where repayment is calculated

Form 8962 (Premium Tax Credit) is the IRS form where reconciliation happens. You file it with your regular federal tax return (Form 1040). Key steps:

1. Get your Form 1095-A: Your marketplace sends this form by January 31. It shows monthly APTC payments and the benchmark Silver plan premium for your area.
2. Calculate your premium tax credit: Using your actual household MAGI and size, Form 8962 determines the credit you qualify for.
3. Compare to APTC received: Line 26 of Form 8962 shows the net result. A positive number means additional credit (refund). A negative number is excess APTC owed.
4. Report on Form 1040: Excess APTC flows to Schedule 2 and adds to your tax liability. Additional credit flows to Schedule 3 as a refundable credit.

If you fail to file Form 8962 and reconcile APTC, the IRS can disallow future advance credit payments - and may assess the full amount owed plus interest.

The OBBBA change: repayment caps eliminated

Before the One Big Beautiful Budget Act (OBBBA), IRC 36B(f)(2) set income-based caps on the amount of excess APTC that had to be repaid. Lower-income households (closer to 100% FPL) had lower caps, providing partial protection against large repayment obligations.

The OBBBA amended IRC 36B(f)(2) to eliminate those caps entirely, effective for taxable years beginning after December 31, 2025 (that is, TY2026 and later). This means:

• For 2027 coverage (reconciled on the TY2027 return):the full excess APTC must be repaid, regardless of income level. There is no cap at any income level.
• A household at 150% FPL that received $10,000 in APTC but only qualified for $8,000 owes the full $2,000 excess - there is no reduced cap.
• A household that crosses 400% FPL and received APTC owes the entire amount received back, not just a portion.

This change makes accurate income estimation significantly more important than it was under prior law. Source: OBBBA (H.R. 1, 119th Congress), amending IRC 36B(f)(2), effective 2026-01-01.

Repayment by income scenario

Here is how the rules play out in different income scenarios for a single filer in 2027 (FPL base: $15,960):

Scenario 1 - Income stays below 400% FPL

You estimated income at $39,900 (250% FPL) but actually earned $47,880 (300% FPL). Your actual applicable percentage is higher than estimated (10.22% vs. the interpolated rate at 250%), meaning your expected contribution is higher. You received more APTC than you qualified for.

Result: You must repay the excess APTC in full. There is no cap under OBBBA rules. The repayment amount depends on how much APTC was advanced and what you actually qualified for.

Scenario 2 - Income crosses the 400% FPL cliff

A single filer estimates income at $60,648 (380% FPL) but ends the year with income of $64,340- just over the $63,840 cliff. The filer received APTC all year but qualifies for exactly $0.

Result: The entire year's APTC must be repaid. If $400/month was advanced ($4,800 for the year), the full $4,800 is owed on the tax return. Under pre-OBBBA rules, a cap may have applied; under current rules, there is none.

Scenario 3 - Income is much lower than estimated

A family of four estimated income at $115,500 but one spouse lost a job and actual income was $66,000. The family received less APTC than they actually qualified for.

Result: Form 8962 shows a net premium tax credit in their favor. The additional credit (the difference between what they qualified for and what was advanced) is added to their refund or reduces the tax they owe. This is a favorable outcome - essentially a refund of premiums they overpaid during the year.

How to avoid a large repayment

The best way to minimize repayment risk is to keep your income estimate current throughout the year:

• Report income changes promptly. Log in to healthcare.gov (or your state exchange) whenever your income changes significantly - a new job, a raise, a layoff, freelance income, or a large one-time event like an asset sale. The marketplace will recalculate your APTC going forward.
• Err on the side of overestimating. If you are uncertain, a slightly higher income estimate reduces your APTC and limits repayment risk. If you end up qualifying for more, you will get a credit at tax time instead of a bill.
• Monitor near the 400% cliff. If your income might approach $63,840 (single) or $132,000 (family of four), watch carefully. Crossing the line by even one dollar costs the entire subsidy for the year.
• Use the calculator. Run different income scenarios through our ACA subsidy calculator to understand how income changes affect your credit and potential repayment.

Overestimating income: you get a refund

Underestimating income leads to a tax bill. Overestimating income works in the opposite direction: you received less APTC than you qualified for. When you file Form 8962, the net premium tax credit flows as a refundable credit on your return.

This means if you paid higher monthly premiums all year because your APTC was set too low, the IRS effectively reimburses you the difference at filing time. There is no penalty for receiving less APTC than you qualified for - it simply means you overpaid premiums throughout the year and get the money back.

From a cash flow perspective, many people prefer to have APTC close to their actual credit to avoid both large repayments and large year-end adjustments. Keeping your marketplace estimate current throughout the year is the best way to achieve this balance.