The Affordable Care Act’s cost-sharing subsidies could be eliminated as soon as President-elect Donald Trump takes office. (Lucas Jackson/Reuters)

Even without Congress repealing the Affordable Care Act, the Trump administration could undermine the law by unilaterally ending billions of dollars the government pays insurers to subsidize the health coverage of nearly 6 million Americans.

Given that insurers would still be required to provide consumers that financial help, such a move could create upheaval in the ACA’s marketplaces — prompting health plans to raise their prices or drop out, according to health-policy experts in both major political parties.

Intervention by the new president to stop the payments “would precipitate a pretty serious crisis almost immediately” unless Congress stepped in, said James Capretta, a resident fellow at the American Enterprise Institute.

The money is for a kind of financial assistance that is less familiar than the tax credits the law gives most people for their ACA plan premiums. These “cost-sharing reductions” are designed instead to lower the deductibles, co-pays and other out-of-pocket fees for nearly half the customers this year.

The payments are expected to total $9 billion in 2017. Eligible consumers would not feel their loss right away because the law still would compel insurers to lower the fees charged. But without government money to make up the difference, the insurers would take an instant hit.

(Jenny Starrs/The Washington Post)

The subsidies could be eliminated as soon as President-elect Donald Trump takes office, a consequence of an unusual lawsuit that House Republicans brought against the Obama administration two years ago.

The GOP’s case, part of its sustained attack on the 2010 law, contends that the cost-sharing reductions to insurers are illegal because Congress has not provided a specific appropriation for them — an argument the administration disputes. In May, a federal district judge ruled in favor of the House but left the subsidies in place while Obama officials appealed the decision.

Once Trump is sworn in, his administration could simply drop the appeal. At that point, the payments would stop, barring a reversal by the Republicans who sued to get rid of the subsidies. Lawmakers would then have to approve funds to keep the payments in place. A three-judge panel of the Court of Appeals for the D.C. Circuit has granted a House request to pause the case until Trump takes office.

Members of Trump’s transition team have not signaled whether the incoming president intends to exercise this power, and sources who have spoken with transition staffers say no decision appears to have been made. Transition spokespersons did not respond to multiple requests for comment.

However, Trump’s choice to lead the Department of Health and Human Services, Rep. Tom Price (R-Ga.), is a vehement ACA critic who has been outspoken in opposing the cost-sharing subsidies. The day of the lower court’s ruling, Price hailed the decision as “a momentous victory for the rule of law and against the Obama administration’s overreach of constitutional authority.”

(Jenny Starrs/The Washington Post)

The uncertainty over cost-sharing’s future is alarming Obama administration officials, insurers that participate in ACA marketplaces and even some ACA detractors such as Capretta.

Andy Slavitt, acting administrator of the Centers for Medicare and Medicaid Services (CMS), the agency that carries out much of the sprawling law, said that ending the subsidies would be “a drastic move” and “an enormous step backwards.”

The payments are one way in which the ACA helps make private insurance affordable for people with relatively low incomes who buy coverage through HealthCare.gov or similar marketplaces at the state level. While the law offers premium tax credits for marketplace customers with incomes up to 400 percent of the federal poverty line, the cost-sharing reductions are for a narrower group. They help those with incomes up to 250 percent of the poverty level — just under $30,000 for individuals or about $60,000 for a family of four — who buy the second-lowest tier of ACA coverage, known as silver plans.

Some 5.9 million consumers — or 56 percent of the people with ACA health plans — benefited from such subsidies in the first half of this year, HHS figures show. This week, two consumers went to court seeking to take part in the appeal. They argue that an end to the subsidies “will produce devastating consequences for the individuals who receive these reductions, as well as for the nation’s health insurance and health care systems generally.”

At America’s Health Insurance Plans (AHIP), preserving the cost-sharing payments is a top priority during the industry trade group’s private conversations with lawmakers over the GOP’s plans to dismantle the health-care law. “Without those subsidies, that is a dramatic financial cost burden that goes to the plans,” AHIP spokeswoman Kristine Grow noted.

Grow predicted that additional plans would follow the insurers that already have withdrawn from ACA marketplaces, citing unexpectedly high-cost customers. “If they feel the market is unstable and there is no pathway, there is a very high likelihood they will pull out of the market at the first logical opportunity,” she said.

Typically, insurers must choose each spring whether to participate in the federal health exchange and state-run marketplaces for the coming year; that timing means the next round of decisions will be made a few months after Trump takes office. But a wrinkle in the plans’ federal contracts gives them a possible way to withdraw much earlier.

The 10-page agreement that health plans sign with the CMS says the agency recognizes that plans designed their coverage and set their prices on the assumption that both premium tax-credits and cost-sharing reductions would be available. “In the event that this assumption ceases to be valid,” the agreement says, plans “could have cause to terminate” their participation.

“Everyone is in limbo right now,” said J. Mario Molina, president of Molina Healthcare, which sells ACA coverage in nine states. Two-thirds of its customers qualify for cost-sharing. As of last month, the company had received $172 million from the government this year for customer subsidies — about 12 percent of Molina’s revenue.

If the payments ended, he said, that would “completely wipe out” the company’s small operating margin. The uncertainty is particularly untimely, coming in the midst of the ACA’s fourth enrollment period, as the insurer prepares to mail membership cards and benefit brochures to those who are signing up.

“We have no choice at this point [but] to go forward,” Molina said. Yet he knows that if Trump stops the cost-sharing, his company will face the hard choice of losing money or dropping out of its ACA marketplaces.

In defending the cost-sharing reductions in court, Obama administration officials have pointed out that without the payments, ACA insurers would ultimately raise their prices, which would mean higher government costs for the law’s premium tax credits. The amount of money going to those credits could jump by as much as 30 percent, the HHS estimates.

For their part, the House Republicans who sued say there is a constitutional issue to prove about the power of Congress over spending. The outgoing administration counters that authority for the subsidies is already embedded in the law.

A House leadership aide, briefing reporters last week, said it is not yet clear how lawmakers would respond if Trump moved to cut off the cost-sharing payments. But, the aide acknowledged, “There are cascading effects about insurance markets we are very aware of.”