Premiums vary widely by state. Generally, a couple in their late 50s or early 60s with an annual income of $65,000 would pay from $1,200 to $3,000 a month for health insurance.
Premiums rose an average 22 percent nationwide in 2017 and are forecast to rise between 20 and 30 percent overall for 2018.
In an analysis released this week based on insurers' rate submissions for 2018, the Kaiser Family Foundation found that individuals and families that don't qualify for a subsidy but are choosing plans on the federal marketplace face premiums 17 to 35 percent higher next year, depending on the type of plan they choose. (Kaiser Health News is an editorially independent program of the foundation.)
A similar increase would be expected for people who also buy on the marketplaces run by some states or buy directly from a broker or insurance company.
The substantial premium increases two years in a row could lead fewer people to buy coverage.
"I'm really worried about this," said Peter Lee, CEO of Covered California, the exchange entity in that state. "We could see a lot fewer people who don't get subsidies enroll." He said that California has taken steps to mitigate the impact for people who don't get subsidies but that "consumers are very confused about what is happening and could just opt not to buy."
There are already signs of that, according to an analysis for this article by the Commonwealth Fund. The percentage of 50- to 64-year-olds who were uninsured ticked up from 8 percent in 2015 to 10 percent in the first half of 2017. In 2013, the figure was 14 percent.
Indeed, the ACA has been a boon to people in this age group whether they get a subsidy or not. It barred insurers from excluding people with preexisting conditions -- which occur more commonly in older people. And the law restricted insurers from charging 55- to 64-year-olds more than three times that of younger people, instead of five times more, as was common.
The law also provided much better access to health insurance for early retirees and the self-employed -- reducing so-called "job lock" and offering coverage amid a precipitous decline in employer-sponsored retiree coverage that began in the late 1990s.
Only 1 in 4 companies with 200 or more workers offered any kind of coverage to early (pre-65) retirees in 2017 compared with 66 percent of firms in 1988, reported the Kaiser Family Foundation. And the vast majority of small firms never did offer such coverage.