With two weeks left to sign up for coverage, California's health insurance exchange announced Monday it has surged past a major milestone -- 1 million enrollments -- well ahead of its March 31 goal.
And a new report suggests what may be the biggest motivator for people when they are choosing a new health plan: cost.
Insurers like Blue Shield of California and Health Net have seen a major jump in market share, thanks to their competitively low rates, according to a report Monday from the Kaiser Family Foundation, while Anthem Blue Cross' dominance has softened.
The shifting landscape indicates the new health law is meeting one of its goals by making health care more competitive. But experts worry plans with low premiums could come with a different cost: Fewer doctors and hospitals could mean fewer choices and longer waits for care.
"The fact is, these are really, really skinny networks of doctors and hospitals that leave a lot of patients without the choices they had before,'' said Jamie Court, president of Consumer Watchdog.
Anthem Blue Cross -- 30.5 percent -- still edged out Blue Shield -- 29.2 percent -- for the largest share of the Golden State's health insurance market when the study was conducted Feb. 28.
But as the report starkly illustrates, Anthem's market share plummeted from 47 percent in the individual market in 2012 before Obamacare policies were available, while Blue Shield's shot up from 19 percent.
The study said it's most likely because Blue Shield was able to offer the lowest premiums in several parts of the state.
Eleven insurers are participating in Covered California, the Golden State's exchange. But the study highlights the four major health insurers as of Feb. 28, when Covered California reported 880,082 enrollees.
"The California market was highly concentrated in 2012, which means it was not competitive,'' said Cynthia Cox, one of the study's three authors. But the exchange market, she said, has altered the landscaped to make it "moderately competitive."
A spokesman for Anthem Blue Cross on Monday said "it's premature to draw and conclusions" from the Kaiser Family Foundation analysis, because it does not include the entire open enrollment period through March 31.
"Market share has changed substantially as more have enrolled via Covered California,"Anthem spokesman Darrel Ng said, "and it's reasonable to expect that this will continue as open enrollment concludes."
Health Net, which previously held only 3 percent of the market in 2012, now has an 18 percent market share. But Health Net also has the lowest premiums in much of Southern California where it is also leading enrollment.
Cox wouldn't say whether the lower prices correlated to narrowed networks, but she did note that Kaiser Permanente is priced relatively higher than its competitors. She said that may be because Kaiser's health care model could not easily narrow its network of doctors and hospitals. Kaiser's market share dropped from 20 percent to 18 percent.
The nonprofit Kaiser Family Foundation is not affiliated with Kaiser Permanente.
Ken Wood, a senior vice president at Blue Shield of California, said the report shows more competition is good for consumers and has led to "attractive rates" offered by Blue Shield.
The narrowed networks that keep the Blue Shield rates down should not be a problem, he said.
"We have what I would describe as narrowed networks, but they are far from narrow," said Wood, noting that the health insurance company has tens of thousands of physicians and hundreds of hospitals for its customers. "It's a worry that exists, but it just hasn't played out.
"This is the beauty of the consumer choice model," said Wood. "People get the plan that best meets their needs."
Covered California spokesman Larry Hicks said the exchange remains confident that the health care provider networks of each insurer is sufficient. He noted that the state reviews and regulates the adequacy of each insurer's networks to be sure there are enough doctors and hospitals.
Moreover, he said, "for hundreds of thousands who were previously uninsured, this new era of care and insurance is a bonanza of doctors and hospitals," he said. "So narrow networks to me is in the eye of the beholder."
Contact Tracy Seipel at 408-920-5343. Follow her at Twitter.com/taseipel.