Analysis: Subsidies will offset ObamaCare 'rate shock'

"Effective outreach and marketing efforts by the exchanges, health plans, consumer groups, and others will be key to educating this population about the availability of subsidized coverage and mitigating the 'rate shock' headlines," Avalere said.

That means premiums are likely to rise for young people who buy insurance on their own, rather than getting it through an employer. Some studies have predicted a massive "rate shock," and the law's critics have stoked fears of an enormous increase.

Other predictions have been more reserved. In California, which recently released the preliminary rates for plans in its insurance exchange, young people would see a lower-than-expected increase in the cost of the cheapest plan.

Those who receive subsidies from the federal government would often pay even less than they're paying now, and some poor young people might not have to pay a premium at all, California officials said.

Nationwide, two-thirds of uninsured people younger than 30 will be eligible for subsidies, Avalere said. Overall, 46 percent of all uninsured people will likely qualify for some level of subsidy.