In November, UnitedHealth abruptly reversed its previously sunny take on ObamaCare and said that the company would have to pull out of the government-run exchanges if market conditions didn’t improve.

UnitedHealth’s bombshell raised the specter, once thought safely in the grave, of the “adverse selection death spiral,” the phenomenon where sick people are more likely to buy insurance, which raises the average expenditure, which means higher premiums, which makes insurance a worse deal for the healthiest members of your insurance pool, which means they drop out, which means your pool is even sicker and average expenditure goes up even more … and there goes the insurance market.

The ObamaCare “risk adjustment” program was designed to support health plans with lots of sick, expensive customers by giving them money from plans with healthier customers. The goal is to help keep insurance markets stable by sharing the “risk” of sicker people and removing any incentive for plans to avoid individuals who need more medical care. Such stability is likely to encourage competition and keep overall prices lower for consumers, while its absence can undermine both and limit coverage choices—the basic principles of the law.

Yet the way the Obama administration has carried out this strategy shows another unexpected consequence of the 2010 health care law. Critics say the risk adjustment program is having a reverse Robin Hood effect—taking money from some plans that are small, innovative or fast-growing, while handing windfalls to some of the industry’s most entrenched players.

In a survey of non-seniors, a New York Times/Kaiser poll found about one-in-five people struggle with medical bills even though they have insurance. Among insured people who reported crushing medical debts, about three-quarters reported putting off vacations, major purchases and cutting back on household spending.

Nearly two-thirds used up all or most of their savings. Far fewer had to resort to second jobs, take on more hours or ask family members for funds (42% to 37%).

Humana will lose money on its 2016 individual market health plans, and the health insurer expects up to 300,000 will drop their coverage by the end of this year, according to a Securities and Exchange Commission filing released late Friday.

It marks the second investor-owned insurer to publicly disclose the problems it is having with the Affordable Care Act’s insurance markets. UnitedHealth Group has lost millions on the marketplace and said it may exit the exchanges by 2017 if things don’t turn around.

A new National Bureau of Economic Research Working Paper shows that workers with employer-based coverage experienced a yearly reduction in wages of $1,200 because of the mandate to expand coverage to 26-year-old children. The researchers from Stanford and Harvard also found that the wage reduction was not concentrated among those with children on their policies, showing that all workers with employer coverage are paying a price for the ObamaCare mandate.

Eager to maximize coverage under the Affordable Care Act, the Obama administration has allowed large numbers of people to sign up for insurance after the deadlines in the last two years, destabilizing insurance markets and driving up premiums, health insurance companies say.

The administration has created more than 30 “special enrollment” categories and sent emails to millions of Americans last year urging them to see if they might be able to sign up after the annual open enrollment deadline. But, insurers and state officials said, the federal government did little to verify whether late arrivals were eligible.

In most states, health insurance premiums on the individual marketplace are rising by double digits under Obamacare. 17 states will face average premium increases of 20% or more. Iowans, for instance, will see their premiums spike by 22% this year. In Minnesota, Alaska, Tennessee, and Hawaii, rates will rise by 30% or more.

Want to know where your state ranks? FreedomWorks has calculated the average rate hike and the range of premium changes individuals purchasing insurance on the individual market will face. Click below to read more.

The Obama administration so far is making little progress in getting more young adults to sign up for health policies on the federal insurance exchange, according to figures released Thursday.

26% of people who signed up for coverage as of Dec. 26 in the 38 states that use the federal exchange were ages 18 to 34, according to a report from the Centers for Medicare and Medicaid Services, which administers the law. That figure is largely unchanged from a roughly comparable two-month period through Jan. 16, 2015.

UnitedHealth Group Inc., the largest U.S. health insurer, said its rates for ObamaCare plans in New York may be too low because the failure of a competing insurer last year might lead to shortfalls in payments designed to stabilize Obamacare markets.

In states like New York, health insurers participating in ObamaCare negotiate annually with regulators to set prices for coverage. UnitedHealth’s rates were set anticipating risk-sharing payments designed to stabilize the new insurance markets, William Golden, the company’s northeast region chief executive officer, said Wednesday. If the loss of a participant reduces the funds available to UnitedHealth, the company’s rates in New York’s ObamaCare market may be insufficient, he said.

The health insurance industry will be watching and waiting to see if antitrust regulators approve several big insurance mergers, whether the Affordable Care Act’s exchange market grows more sustainable, and whether states adopt new regulations governing provider network adequacy.

Looming above all those issues is the possibility of the election of a Republican president who would seek to jettison the ACA framework and replace it with an entirely different healthcare financing framework.