Early data from insurers, brokers and consultants suggest that the marketplaces are popular with consumers who were previously covered elsewhere, raising questions about a law intended to expand coverage to millions of healthy, uninsured Americans to help offset costs.

A survey by management consulting firm McKinsey & Co. found that only 11 percent of consumers who purchased new coverage under ObamaCare were previously uninsured. The survey was based on a sampling of 4,563 consumers between November and January, according to The Wall Street Journal.

HealthMarkets Inc., an insurance agency that signed up about 7,500 people in exchange plans, reported that 65 of its enrollees had prior coverage, the report said. Fifteen percent of enrollees had their individual plans canceled, and 40 percent switched over from previous individual plans.