But the most immediate issue to be addressed is funding subsidies for the lowest-income enrollees.
The changes come as insurers are figuring out their plans for 2018.
Open enrollment this fall (for 2018 health insurance coverage) would shorten to six weeks, down from three months. (It exempts certain silver plans for low-income consumers from the change.) So, for example, a bronze plan might cover only 56 percent of costs and silver 66 percent.
Numerous changes announced Thursday follow recommendations from insurers, who wanted the government to address shortcomings with HealthCare.gov markets, including complaints that some people are gaming the system by signing up only when they get sick, and then dropping out after being treated.
The cost-sharing subsidies, estimated at $7 billion year, have been challenged in a court case that's now on hold.
The cost-sharing payments are the less well-known part of the financial help that the Affordable Care Act provides, but the support is baked into the plans bought by more than half of the 12.2 million people insured through the exchanges.
Under the new rule, 100 percent of those applications would be required to undergo preapproval verification - beginning in June 2017.
Daria Cross of Redlands, Calif., was one of more than seven million people who this year took advantage of the reductions, and said they have been a lifesaver for her family.
"While these steps will help stabilize the individual and small group markets, they are not a long-term cure for the problems that the Affordable Care Act has created in our health care system", said Seema Verma, administrator of the Centers for Medicare & Medicaid Services, which runs Obamacare.
Without the payments, known as cost-sharing reductions, insurers could pull out of ObamaCare exchanges altogether or spike premiums, causing chaos in the health insurance market.
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He said that consumers may not be aware of how much they benefit from the federal payments unless they are revoked. Without the funding, millions of Americans who buy their own plan will be harmed and premiums will go up almost 20 percent, she said. Most often those exemptions came from people whose income was so low (less than $10,350 for an individual) that they are not required to file a tax return, or from Americans who lived overseas for most of the year, or from people for whom the cheapest available insurance was still unaffordable (costing more than 8 percent of their household income).
House Energy and Commerce Committee Chairman Frank Pallone Jr.
The Trump administration's new rule seeks to stabilize the Obamacare insurance marketplace while Congress continues to work on repealing Obamacare. That will likely result in fewer people enrolling but will also probably mean insurers will get a full year's worth of premiums.
"Our position remains unchanged: drop repeal, stop undermining our healthcare system and we will certainly sit down and talk about ways to improve the Affordable Care Act", Schumer said, according to The Hill.
Moreover, the rule gives states broader authority by removing the federal government's role in overseeing doctor and hospital networks included in insurance plans.
"Some states are good at that".
But some specialists in the health law, including Christopher Condeluci of CC Law & Policy in Washington, D.C., saw the initial proposal released in February by HHS as helpful for insurers, though he also thought more adjustments were necessary.
Insurers and major medical groups have warned that not funding the payments could wreak havoc in individual insurance markets, and penned a letter to Trump the same day urging him to maintain funding to the subsidies. But the insurance industry quickly said the changes don't go far enough.
Recent Avalere analysis found that exchange enrollment has fallen well below initial projections, and Avalere data for 2017 exchange plans show that one in three regions in the USA will have no insurer competition.