The Obama administration on Thursday said that millions of people with health insurance purchased in the new federal marketplace would need to switch to different health plans to avoid increases in premiums or reductions in the subsidies they received from the government.
In other words, officials said, consumers may need to find new health plans if they want to make sure their coverage under the Affordable Care Act is, indeed, affordable.
But, the officials emphasized, more health insurance plans will be on sale in the federal marketplace next year, and most consumers will be able to find health plans for less than $100 a month, with subsidies.
“More than seven in 10 of our customers can find lower prices by shopping,” said Kevin J. Counihan, the chief executive of the federal insurance marketplace. “Roughly eight in 10 of our customers can get coverage for less than $100 a month after tax credits.”
So far, it appears relatively few consumers have taken the advice offered by federal officials.
When the open enrollment period began on Nov. 15, about 6.7 million people already had coverage through exchanges created under the 2010 health care law. As of Nov. 28, only 6 percent of them had returned to the marketplace and renewed their coverage or selected different plans for 2015.
If people take no action by Dec. 15 to renew or replace policies purchased on the federal exchange, they will be automatically enrolled in the same plan or a similar plan, effective Jan. 1. Consumers have until Feb. 15 to change or make their selections for the rest of 2015.
In much of the country, Mr. Counihan said, consumers will see more choices and competition in the marketplace. “Ninety percent of our customers now can choose from three or more insurers, up from 74 percent in 2014,” he said.
Competition tends to reduce prices, but in many places, Mr. Counihan said, it has also reduced subsidies, which are tied to the price of a benchmark “silver plan.” On average, such plans pay about 70 percent of the cost of care for a typical consumer.
While consumers can usually save money by switching plans, they will often face higher premiums or lower subsidies if they remain in their current plans, federal officials said.
“For the vast majority of people, if they stay in the same plan, they will see rate increases in the single digits, to high single digits,” said Andrew M. Slavitt, the No. 2 official at the Centers for Medicare and Medicaid Services.
Some consumers have complained about price increases for 2015. But Richard G. Frank, an assistant secretary of health and human services, said that premiums for the benchmark silver plan held stable, with an increase of only 2 percent on average in states using the federal exchange.
Mr. Frank said the price increases were “far lower than they have been historically.” In the past, he said, consumers buying insurance on their own regularly faced increases of 12 percent to 15 percent a year.
Prices vary greatly from state to state and even among counties in the same state. A report issued by the administration on Thursday showed that lower premiums often, but not always, correlated with more competition.
In New Hampshire, for example, where the average number of health plans increased to 38 per county in 2015, from 10 in 2014, the average premium for a 27-year-old in a benchmark silver plan declined by 14 percent, to $205 a month, from $237.
And in Mississippi, where the average number of plans rose to 27 per county, from 13 this year, the average premium for the benchmark plan fell 20 percent, to $249 from $311.
By contrast, in large parts of Alaska, where the number of health plans declined to 28, from 34, the premium for a benchmark silver plan for a family of four increased 28 percent, to $1,624 in 2015, from $1,265 this year.
And in Wyoming, the number of plans more than doubled, to an average of 40 per county, but premiums on the federal exchange are among the highest in the country. For a benchmark silver plan, the price will rise 5 percent for a family of four, to an average of nearly $1,300 a month, the administration reported.
Nearly two-thirds of people with marketplace coverage in the past year had silver plans. The administration said they could save nearly $500 a year by selecting a different silver plan for 2015.