Californians were responding to Monday's deadline for gaining health insurance with heavy activity on the marketplace's website and call centers.
Covered California, the agency operating the exchange, had no current plans to extend the deadline by another day, as the Obama administration announced it was doing for the 36 states using the federal health insurance exchange. California runs its own exchange under the federal Affordable Care Act.
Those who enroll by the end of Monday will have coverage starting Jan. 1, but will have until Jan. 6 to pay for their policies.
Agency spokesman Larry Hicks said California's enrollment website has been running smoothly with no technical problems.
"I can say that volume was heavy, and that was expected," he said. "There were no reported performance issues, and none are expected today."
Enrollments have surged on the California health exchange as Monday's deadline approached. Only about 30,000 people signed up for coverage in October, the first month that the exchange was open for business, but enrollments had been running about 20,000 or more a day over the past week.
More than 109,000 people had signed up for coverage through the end of November, the last official figures released by Covered California show.
While Monday was the deadline to get coverage that will start in the new year, consumers will have until the end of March to buy coverage and avoid the federal tax penalty under the federal health reform law.
"(Monday)'s an important milestone, but it's not the end," Hicks said. "We expect to enroll tens of thousands if not hundreds of thousands more through March 31."
Last week, Covered California Executive Director Peter Lee said he was optimistic the exchange will meet its enrollment target of 700,000 by the end of March.
California's exchange has operated far better than the federal government's, but the system has not been glitch-free.
The agency has been working through a backlog of paper applications that at one point stood at 25,000. Lee set a Monday deadline to have all that information typed in to the computer system so it could be transmitted to insurers.
About 1.1 million Californians also had their existing individual insurance policies canceled because they didn't meet the tougher standards of the federal law, a development that prompted California to extend the sign-up deadline from the original date of Dec. 15. Because the enrollment deadline was extended, Covered California and insurers also agreed to extend the policy payment deadline by five days.
The cancellations forced some consumers into more expensive plans. Many were upset over the change, especially after President Barack Obama had repeatedly promised that people who liked their health coverage could keep it.
Despite the occasional problems, health insurance companies are generally pleased with how the marketplace is operating in California, said Patrick Johnston, chief executive of the California Association of Health Plans, which represents insurers.
He described the level of consumer interest in signing up for health care policies as enormous and said insurance companies had responded by increasing staff and boosting their outreach to private insurance brokers.
"The surge is a challenge, but health plans are meeting it," Johnston said in a telephone interview Monday.
So far, enrollment has skewed toward older people. That could cause financial problems for insurers if the pool becomes heavily weighted toward those who require more medical care and does not include enough younger and healthier people.
In response, Covered California has been ramping up its marketing efforts to the younger demographic.