MADISON, Wis. (AP) -- A new report says insurers who sell medical policies to Wisconsin individuals will face an 80 percent increase in claims costs by 2017 thanks to the national health care law.

The Society of Actuaries study says costs will rise largely because of spending on sicker people and other high-cost groups who will gain coverage under the Affordable Care Act. Wisconsin Office of the Commissioner of Insurance spokesman J.P. Wieske says 24,000 Wisconsin residents with serious medical conditions will be moving into the private market as of Jan. 1.

Medical claims are considered the biggest driver of health insurance premiums' cost. The report doesn't make similar estimates for employers' plans.

The White House has disputed the study, saying it ignores cost-relief components such as tax credits.