The vast majority of people who bought health insurance through the state's new online marketplace chose plans offered by CareFirst BlueCross BlueShield, the state's dominant insurer. Even more called the carrier and enrolled directly, according to data obtained from the insurer.

CareFirst reported for the first time that it had signed up more than 53,000 people through the health exchange as of April 9. The exchange reported Friday that almost 65,200 people had enrolled in private insurance through the four carriers selling on its website in the same time frame.

Another 58,000 people called CareFirst directly to sign up, many possibly because the exchange experienced technical problems so severe since its launch Oct. 1 that it is being scrapped and replaced with a system used in Connecticut. About 80 percent of people enrolled in CareFirst plans have paid, the insurer said.

Carolyn Quattrocki, interim director of Maryland's exchange, said CareFirst's strong showing is not a surprise. Other carriers may be more competitive during the next open enrollment in November, she said.

"CareFirst has been the dominant carrier for a long time, and still other carriers wanted to remain in the state despite the fact that CareFirst has a larger percentage," she said. "One of the goals of the health benefit exchange here and nationally is to provide a marketplace where it's easier for consumers to compare quality and costs."

CareFirst declined to comment on the enrollment numbers.

Though open enrollment ended March 31, the insurers and the exchange continue to sign up consumers who reported problems with the process. Enrollment is expected to continue for about a month and could add thousands more to the rolls —almost 2,200 signed up in the last week, the exchange said.

The three other insurers declined to provide their enrollment numbers, though they split a much smaller piece of the pie.

The exchange has reported that it has enrolled 313,681 people, the majority in Medicaid, the federal-state program for the poor. But the total jumps to nearly 381,400 when those who bought CareFirst policies directly through the insurer are considered.

That pushes the state far closer to its initial target of enrolling 150,000 people in private plans, and well above a revised goal of at least 70,000 people. The state also now far exceeds its overall goal of signing up 260,000 people in Medicaid or private plans compliant with the provisions of the new health law.

Quattrocki said exchange officials had no expectations about how many people would sign up outside the exchange but have been pleased with CareFirst's direct enrollment. She did not know how many signed up directly with other carriers.

Neither the exchange nor CareFirst could say how many people already had insurance before they enrolled. The state plans to conducts surveys of the estimated 400,000 who were uninsured and qualified to enroll in public or private coverage on the exchange.

But CareFirst's dominance in the state may have consequences for consumers next year and down the road, said Bradley Herring, a health economist at the Johns Hopkins University.

Herring said CareFirst's growing market share means it could offer even lower premiums next year because it has more negotiating power with doctors and drug companies as well as lower administrative costs per customer. In turn, that could attract even more consumers during the next open enrollment, he said.

That could make competing even harder for other insurers, who already had to contend with CareFirst's strong name recognition and often lower premiums. They could be forced to raise premiums or even decline to offer policies, reducing choice and eventually giving CareFirst the ability to raise its premiums, Herring said.

"CareFirst has dominated the individual and small group market here in Maryland for a while, so dominating the exchange shouldn't be so surprising," Herring said. "You would have thought the functionality of a website that puts all plans on equal footing would have helped the other plans. The exchange's troubles were probably a big factor."

Herring said many likely picked a carrier they were familiar with when they couldn't easily comparison shop and had to sign up on paper or directly with an insurer.

Other insurers have said the lack of a properly working website has harmed their enrollment, including Dr. Peter Beilenson, who founded and heads Evergreen Health Co-op under the new health law. Beilenson said he couldn't compete early on against CareFirst because no one could see what he had to offer and few had heard of the co-op. He had to switch focuses to small businesses and do his own marketing.

Now, he said brokers are selling his policies at a fast clip to those businesses, and he has few individual customers. He expects to gain approval to offer policies to large companies soon. And he's hopeful that he'll be more competitive in the individual market in the fall. Evergreen plans to drop premium prices and maintain benefits to lure more people, he said.

He figures people who didn't really shop around and went with the lowest premium will want to switch plans because they've discovered they have deductibles that are hard to reach. Another consideration is federal subsidies to help pay for plans. People purchasing directly with an insurer instead of on the exchange were unable to receive subsidies.

"We've learned a lot in the last year," Beilenson said. "We'll be more competitive and the exchange will work better. And we'll be known for a year and before we were completely unknown."

Meredith.cohn@baltsun.com