If you owe taxes because of health insurance, the reason is almost always the same: the advance premium tax credit the government paid to your marketplace insurer during the year was larger than the credit your actual income entitled you to, and you have to pay the difference back when you file. For the 2026 tax year, that gap can be far bigger than in recent years because the enhanced subsidies expired, the 400% income cliff returned, and the limits that used to cap how much you had to repay are gone.1Congress.gov. Enhanced Premium Tax Credit and 2026 Exchange Premiums2Internal Revenue Service. Updates to Questions and Answers about the Premium Tax Credit (FS-2025-10)
How the Credit Turns Into a Tax Bill
When you enrolled in a marketplace plan, you estimated your household income for the year. The marketplace used that estimate to calculate a premium tax credit and sent most or all of it directly to your insurer each month, which is why your monthly premium felt manageable. At tax time, the IRS runs the numbers again using what you actually earned. That reconciliation happens on Form 8962, which every taxpayer who received advance credits must file.3Internal Revenue Service. Reconciling Your Advance Payments of the Premium Tax Credit
If the advance payments were larger than the credit you actually qualified for, the excess is added to your tax liability. An expected refund shrinks or disappears; an existing balance grows. If the advance payments were smaller than what you qualified for, the extra credit goes onto your return and increases your refund or reduces what you owe.
You need Form 1095-A from your marketplace to complete the reconciliation. It lists your monthly premium, the second-lowest-cost silver plan premium for your area, and the advance payments made on your behalf.4Internal Revenue Service. Health Insurance Marketplace Statements Check every line. A wrong premium figure or an incorrect SLCSP amount will throw off Form 8962 and either delay your refund or produce a bill you shouldn’t owe.
Why Your Actual Credit Came in Smaller
The usual culprit is income that ended up higher than what you projected at enrollment. Even a modest increase can shrink the credit, and the income the IRS uses is modified adjusted gross income (MAGI), not just the wages on your paycheck. MAGI adds back untaxed foreign income, non-taxable Social Security benefits, and tax-exempt interest.5HealthCare.gov. Modified Adjusted Gross Income (MAGI) A side gig, a capital gain, a spouse picking up extra shifts, a bonus you didn’t expect, unemployment that ended earlier than planned: any of these can push your MAGI above your estimate.
Life changes do the same thing. Getting married combines two incomes into one household figure. A child aging out, a dependent moving out, or a divorce changes your household size and the poverty-level percentage your income falls under. The credit is calculated on a sliding scale, so every shift matters.
Why 2026 Bills Are Bigger
From 2021 through 2025, enhanced subsidies softened both edges of the system: higher-income enrollees could still qualify, and lower-income households were protected by caps on how much excess credit they had to repay. Both features ended on January 1, 2026.1Congress.gov. Enhanced Premium Tax Credit and 2026 Exchange Premiums
The 400% FPL Cliff Is Back
If your household income exceeds 400% of the federal poverty level, you are no longer eligible for any premium tax credit. For a single person in 2026, that threshold sits at roughly $63,840.6Internal Revenue Service. Eligibility for the Premium Tax Credit Someone who estimated $60,000 at enrollment and actually earned $65,000 owes back every dollar of advance credit received during the year. Under the enhanced rules, that same person would have kept at least a partial subsidy.
Repayment Caps Are Gone
In prior years, lower-income households had a ceiling on how much excess advance credit they could be forced to repay, no matter how far off the income estimate turned out to be. Starting with the 2026 tax year, there are no repayment caps for any income level. You owe back the full difference between what your insurer received and what you actually qualified for.2Internal Revenue Service. Updates to Questions and Answers about the Premium Tax Credit (FS-2025-10) An income estimate that was off by a few thousand dollars used to produce a few hundred in repayment; now it can produce thousands.
The expected-contribution percentages the IRS uses to calculate the credit also went up for 2026, ranging from 2.10% of income at the low end to 9.96% near the top of the eligibility range.7Internal Revenue Service. Rev. Proc. 2025-25 If you enrolled expecting a subsidy similar to last year’s, the credit itself is smaller before any income-change effects are added in.
Employer Coverage You Were Eligible For
You generally cannot receive marketplace premium tax credits if your employer offered coverage that met two tests: it covered at least 60% of expected health costs, and the employee’s share of the premium was no more than 9.96% of household income for the 2026 plan year.8Internal Revenue Service. Minimum Value and Affordability If the plan passed both tests and you took marketplace subsidies anyway, every dollar of advance credit becomes repayable.
The same logic applies to an individual coverage health reimbursement arrangement (ICHRA). If your employer’s ICHRA made your self-only lowest-cost silver plan affordable, you cannot receive premium tax credits even if you declined the ICHRA.9HealthCare.gov. Individual Coverage Health Reimbursement Arrangements (HRAs) A taxable health stipend is different: it shows up as regular wages on your W-2, which raises your MAGI and can shrink the credit you qualify for even though it doesn’t disqualify you outright.
If You’re Self-Employed
Self-employed workers can deduct 100% of health insurance premiums for themselves, a spouse, dependents, and children under 27 as an above-the-line deduction, which reduces your AGI and your MAGI.10Office of the Law Revision Counsel. 26 USC 162 – Trade or Business Expenses Two limits trip people up. The deduction cannot exceed the net profit of the business the plan is established under, so a weak year yields a smaller deduction. And you cannot claim it for any month you were eligible for a subsidized plan through any employer, including a spouse’s.11Internal Revenue Service. Instructions for Form 7206
There is also a circular calculation unique to self-employed marketplace enrollees: the credit depends on MAGI, MAGI depends on the self-employed health insurance deduction, and the deduction depends on how much premium you paid net of the credit. The IRS requires an iterative calculation to resolve this, laid out in Publication 974. Getting it wrong in either direction produces a surprise at filing.
What Happens If You Don’t Reconcile
If you received advance credits and don’t file Form 8962, the IRS may send a Letter 12C asking for it and holding your refund until you respond. Ignore that letter and the return can be rejected outright. The longer-term consequence is harsher: miss the reconciliation for two consecutive years and the marketplace can cut off your advance payments going forward.12CMS. What Does Failure to File and Reconcile Mean? At that point you have to pay the full unsubsidized premium each month and claim any credit only as a lump sum at tax time, which prices many households out of their coverage.
One Thing That Isn’t the Reason
The federal penalty for lacking coverage has been zero since 2019, so going uninsured no longer adds anything to your federal tax bill.13HealthCare.gov. Exemptions from the Fee for Not Having Coverage Several states and the District of Columbia do run their own individual mandates with penalties collected through state income tax returns, so if your bill is on a state return rather than federal, that may be why.
Keeping It From Happening Again
The single most effective step is reporting income and household changes to the marketplace as they happen, not at year-end. A raise, a new job, marriage, a birth, a death, a dependent leaving the household: each one changes your credit, and updating promptly lets the marketplace adjust the advance payments going out to your insurer. Smaller monthly adjustments throughout the year mean a smaller gap at reconciliation.
Review your Form 1095-A line by line when it arrives in late January. If the monthly premium, the SLCSP figure, or the advance payment amounts don’t match what you actually experienced, contact the marketplace for a corrected form before you file. A corrected 1095-A that arrives after you’ve already filed will often mean amending your return. For self-employed enrollees, the iterative calculation is a situation where tax software or a preparer who knows Publication 974 is worth the cost, because an error in either direction shows up as money owed.