About 12.7 million consumers selected a health plan or were automatically re-enrolled through the Healthcare.gov platform or a state insurance marketplace in the third open-enrollment period, which ended Jan. 31. The estimate from the Department of Health & Human Services exceeded the goal and included 4 million consumers who gained coverage from an exchange for the first time.

That said, enrollment is significantly below what was originally projected by the Congressional Budget Office and growth was slower than in the previous open-enrollment periods. Combining that with other developments — a few insurers say they may drop out of the marketplace business, and several nonprofit, state-licensed co-ops authorized by the Affordable Care Act went out of business — prompts some observers to question whether the insurance marketplace concept is going to pan out.

Not to worry, says Sara Collins, vice president for health care coverage and access program at the Commonwealth Fund. She points out that consumers have more choices on the exchanges — on average, five carriers  — in the most recent open-enrollment period than they did in the first year. “We have seen competition and stability in the marketplaces,” she says.

And they will become more stable as more individuals buy insurance through the exchanges. Collins identifies two reasons that she is confident exchange enrollment will grow. For one, more than 8 million people have individual insurance policies outside the marketplaces and many of those likely hold “transitional” policies that were not compliant with the Affordable Care Act, but those policies go away in 2017.  “Many of these people may come into the marketplace at that point,” Collins says.

Plus, most of the 10 million individuals who remain uninsured are eligible for subsidies to buy insurance through the marketplaces. They may not yet fully understand the penalties for not being insured or the subsidies available to help them — which presents an opportunity for health systems.

“Helping people understand what their options are will increase the number of people who come into marketplace plans and help increase the stability of the marketplaces over time,” she says. “And it will also benefit health care providers’ bottom lines.”