Millions of Americans buying their own health insurance are facing sharply higher bills this winter, and the reason is a single policy change with an unhelpful name: the ACA subsidy cliff. Open enrollment for 2027 coverage opened on 1 November 2026 and runs to 15 January 2027, and the shoppers logging on this month are finding that the help they received in recent years has shrunk or disappeared entirely. This guide explains what the subsidy cliff is, why it came back, what it has already cost households, and what happens next, including a Senate vote expected in mid-December.

Start with the basics. The Affordable Care Act, known as Obamacare, created health insurance Marketplaces where people without job-based cover, Medicare or Medicaid can buy a plan. Most buyers get a federal Premium Tax Credit that lowers the monthly premium. The size of the credit depends on income and on the price of a benchmark silver plan in their area. Under the original ACA rules, that help stopped abruptly at a fixed income line: households earning more than 400 percent of the federal poverty level received no credit at all, however expensive their premiums were. That sudden cut-off is the cliff. A household earning one dollar above the line could lose thousands of dollars of help overnight, while a household just below it kept the full credit.

To see how steep that is, consider the example modelled by KFF, the nonprofit health policy research organisation. A 60-year-old earning 62,000 dollars a year, about 396 percent of the federal poverty level, would pay roughly 6,175 dollars a year for a benchmark silver plan, about 10 percent of income. The same 60-year-old earning 64,000 dollars, about 409 percent of the poverty level, would pay the full unsubsidised price of about 14,931 dollars, roughly a quarter of income. Two thousand dollars of extra earnings would cost more than 8,700 dollars in lost help. That is the cliff in action, and it falls hardest on older, middle-income people, because their premiums are the highest and the credit they lose is the largest.

For five years, the cliff did not exist. The American Rescue Plan Act of 2021 expanded the premium tax credits in two ways: it raised the size of the credits for people who already qualified, and it removed the 400 percent income ceiling altogether, so that nobody paid more than 8.5 percent of their income for the benchmark plan. The Inflation Reduction Act extended those enhanced credits through the end of 2025. During that period, Marketplace enrollment grew rapidly, reaching a record 21.8 million people with effectuated coverage in 2025, meaning people who had actually paid their premiums and were covered.

Then the enhanced credits expired on 31 December 2025, and Congress did not extend them. From 1 January 2026, the subsidy rules reverted to the original ACA formula: the 400 percent ceiling returned, the required contribution percentages rose, and households above the line lost all help. The effect was immediate and large. KFF's analysis of federal data found that average monthly premium payments, after tax credits, rose 58 percent, from 113 dollars in 2025 to 178 dollars in 2026. The average deductible, the amount a person must pay out of pocket before their plan starts paying, grew by 37 percent, or more than 1,000 dollars, from 2,759 dollars in 2025 to 3,786 dollars in 2026, the steepest increase in the programme's history.

Faced with higher bills, many shoppers changed their behaviour. Sign-ups for bronze plans, the cheapest and thinnest cover, jumped from 30 percent of plan selections to 40 percent, growing from 7.3 million to 9.2 million people. Others dropped out altogether. KFF found that February effectuated enrollment fell to 19.2 million people in 2026, down from 21.8 million in 2025, a decline of 12 percent and the first fall in seven years. Every state except New Mexico saw enrollment drop. The one exception proves the rule: New Mexico fully replaced the expired federal credits with state-funded subsidies, and its enrollment grew 14 percent, with the highest effectuation rate in the country at 96 percent, against a national rate that fell from 90 percent to 83 percent. A KFF survey found that eight in ten people who changed their cover or became uninsured cited cost as a reason.

The damage did not stop with premiums. Because the enhanced credits are gone, the full repayment rule for excess advance credits now applies without a cap. Under the One Big Beautiful Bill Act, signed in July 2025, people who received more advance credit during the year than they were entitled to must now repay the full amount, where previously repayment was capped. That matters because advance credits are estimated from predicted income, and a pay rise, a new job or overtime can leave a household owing money at tax time. The credits themselves have not ended: the regular Premium Tax Credit continues for households below the income ceiling. What ended was the enhanced version that made the help bigger and removed the cut-off.

What about 2027? Open enrollment for 2027 coverage opened on 1 November 2026 and runs to 15 January 2027, with 15 December the deadline to enrol for cover starting on 1 January. With rates now final, KFF finds benchmark silver premiums up 13 percent on average for 2027, or 11 percent in states using the federal HealthCare.gov platform and 16 percent in states running their own platforms. The enhanced credits have still not been restored, so people above 400 percent of the poverty level pay the full premium. For 2027 coverage, the 400 percent line is about 63,840 dollars for a single person and about 132,000 dollars for a family of four. The Congressional Budget Office has estimated that without the enhanced credits, 2027 gross benchmark premiums would be about 7.7 percent higher than they would have been if the credits had been extended. From 2027, refugees, asylees and some other lawfully present immigrants can still buy Marketplace cover but no longer receive tax credits.

The politics of the cliff are as tangled as the policy. The subsidies became entangled in the record 41-day government shutdown that began on 1 October, when Democrats demanded an extension of the credits as the price of reopening the government. On 11 December 2025 the Senate voted on two competing proposals and rejected both: a Democratic plan for a three-year extension drew 51 votes, short of the 60 needed, and a Republican alternative built around health savings accounts also failed. On 8 January 2026 the House passed a three-year extension by 230 votes to 196, with 17 Republicans joining Democrats after a discharge petition forced a vote, but the bill has sat on the Senate calendar since February with no vote. KFF polling found 67 percent of the public said Congress was wrong not to extend the credits, while 63 percent of Republicans said it was right.

The shutdown itself ended when eight Democratic senators broke with their party to advance a funding deal, with a final cloture vote of 60 to 40 and Senator Rand Paul the only Republican voting against. That agreement, described by the National Low Income Housing Coalition, would fund most federal programmes through 30 January and includes three full-year spending bills, reverses the layoffs of furloughed federal workers imposed since 1 October, and guarantees legally mandated back pay for furloughed and excepted workers. What it does not do is extend the ACA tax credits. The Senate is expected to vote on the ACA extensions in mid-December, but the agreement does not guarantee a vote. That December vote, if it happens, is now the next real chance for an extension before the 2027 plan year is fully under way.

Who is most affected? The cliff hits hardest at the boundary. A self-employed worker, a freelancer or a small business owner whose income varies from year to year can cross the line with a single good month. Older buyers face the biggest losses because age is the main driver of premium prices, and a 60-year-old just above the line loses a credit worth thousands. Younger, healthier buyers lose less in absolute terms but still face the full premium, and the shift towards bronze plans means many are now paying less each month but facing deductibles of nearly 3,800 dollars before their cover helps. The result is a thinner safety net: fewer people covered, and those who remain covered paying more before their insurance starts working.

There are a few practical points for anyone shopping in this open enrollment period. First, the dates matter: enrol by 15 December for cover starting 1 January, and by 15 January for the last chance at 2027 cover on the federal platform. Second, the subsidy is calculated on household income, so an accurate estimate matters more than ever, because underestimating income can now mean a larger repayment at tax time. Third, state-run Marketplaces and state-funded help can change the picture: New Mexico's experience shows that state action can fully offset the federal change, and several states that run their own platforms and partly offset the lost credits saw smaller enrollment drops than states using the federal platform. Checking the official HealthCare.gov site or a state Marketplace, rather than relying on last year's premium, is the only reliable way to see what a 2027 plan actually costs.

It is worth being clear about what has not changed. The Affordable Care Act itself has not been repealed. The Marketplaces are open, the regular Premium Tax Credit still exists for households below the income ceiling, and insurers must still cover pre-existing conditions and essential health benefits. What changed is the generosity of the help and the return of a hard income cut-off that Congress built into the original law, suspended for five years, and then allowed to return. The question now is whether the Senate's expected December vote produces an extension, and if so on what terms. Until then, the cliff is the law, and the 2027 open enrollment figures will show how many more households decide the new prices are simply more than they can pay.