The Kaiser Family Foundation report found premiums for popular low-cost plans under the health care law are projected to increase an average 11 percent in 2017.
Among the sharpest projected increases are: 26 percent in Portland, Ore.; 21 percent in the District of Columbia; and 16 percent in New York City.
The study focused on the two least-expensive -- and very popular -- "silver" policies. It specifically examined the impact of rising premiums on those whose income exceeds the limit to get government subsidies to defray the cost of mandatory insurance.
The income cutoff for those tax credits is $47,520 for an individual and $97,200 for a family of four.
