"There are several reasons to believe there could be significant premium increases in 2015, e.g., underpricing in 2014, increases in health care costs, and pressure to broaden networks. But the dominant force behind the surprisingly low premiums in 2014 remains intact -- the strong incentives for markets to be highly competitive, which forces insurers to set premiums aggressively to attain or retain market share. These incentives should be even stronger in 2015 with increased enrollment and a more stable risk pool."