"We've certainly seen pretty significant premium increases this year, as many [insurance] carriers exit or significantly scale back participation," said Elizabeth Carpenter, senior vice president of the Avalere Health consultancy.
Estimates say more than 1 million consumers will have to pick a new insurance carrier because their current insurer is exiting the Obamacare exchanges, Carpenter said.
Those exchanges opened for business in 2013, with the largest one — the federal marketplace HealthCare.gov — crashing upon launch, and struggling for more than a month to enroll meaningful numbers of people.
HealthCare.gov, which now serves residents of 39 states, was soon fixed, and has since run smoothly.
The key question facing Obamacare this year is whether HealthCare.gov and the state-run insurance exchanges can significantly grow enrollment beyond the nearly 12 million people who signed up during the last open-enrollment period. Insurers want more healthy customers to sign up, to offset the costs of less-healthy customers.
Another big question is how the many consumers who don't get financial assistance will deal with increasing costs of coverage. About 85 percent of people who buy plans on Obamacare exchanges qualify for subsides that can lower the cost of their premiums, even if those premiums are rising by a large amount.
That financial aid, which comes in the form of tax credits, is available to people whose household incomes fall between 100 percent and 400 percent of the federal poverty level (or $24,300 to $97,200 for a family of four).
But people who earn more than 400 percent of poverty don't get financial aid — and thus must bear the entire brunt of the price hikes.
"Certainly, if you aren't getting a tax credit subsidy in the individual market, you are likely to face significant premium increases, depending on where you live," Carpenter said. She noted that the actual price a consumer will pay, particularly one who isn't subsidized, is directly related to the state, county or insurance rating area where they live.
The Obama administration last week revealed that the price of a so-called "benchmark" plan sold on HealthCare.gov is growing by an average 25 percent. Benchmark plans, whose prices are used to calculate the amount of subsidy that eligible consumers receive, are the second-lowest-cost "silver" plan. Silver plans, which are the most popular type of exchange-sold plans, cover 70 percent of their customers' health costs.
Some states are seeing premium price hikes for their benchmark plans well above that average. In Arizona, which will go from five insurers selling Obamacare plans this year to just four in 2017, benchmark plans are rising by 116 percent on average.
Oklahoma, which will have just one insurer offering Obamacare plans in 2017, down from two this year, has benchmark plans rising by an average 69 percent. In Tennessee, benchmark plans are rising an average 63 percent.
Many other states are seeing double-digit price hikes. A handful of others, including Michigan and New Jersey, are seeing single-digit premium increases. In Indiana, the benchmark plans are actually decreasing in price, by an average 3 percent.
When CNBC noted that state-wide drop in benchmark plans last week, spokesmen for Indiana Gov. Mike Pence, the Republican vice presidential nominee, said reporting only that figure was "misleading." They cited data they said shows that the average rate increase for all plans sold in the state are rising by an average of 18.7 percent.
The rising average premiums nationally are the result of a number of insurers low-balling their initial Obamacare prices, and then being faced with a customer base that used more in health services than they paid in premiums. Insurers are also dealing this coming year with the expiration of two Affordable Care Act programs that were designed to mitigate the financial risk of selling Obamacare plans.