A group of state insurance officials said they were told by the White House on Thursday that 35 percent of ObamaCare's enrollees are under 35 years of age.
That figure represents a four-point increase since March 1, indicating that health insurance enrollments from young people increased, as expected, toward the end of the sign-up deadline.
The percentage did not appear to refer exclusively to young adults between the ages of 18 and 35, whose participation is necessary to keep prices stable on the exchanges.
"That's a pretty good number in terms of trying to make sure that we have a healthy [risk] pool," NAIC President-Elect Monica J. Lindeen said of the 35 percent.
Current NAIC President Adam Hamm said he wanted to see more detailed figures before making a judgment.
The group's leadership called it a "very productive" meeting despite commissioners' diverse views on the healthcare law itself. Forty-four insurance commissioners met with Obama and his senior staff for more than an hour.
The meeting came shortly before Obama was expected to announce a new total enrollment figure for the exchanges. White House officials did not release a number to NAIC members, commissioners said.
State insurance regulators will play a crucial role approving 2015 rates for the marketplaces over the next several months, a topic that will loom large in the midterm elections.
The administration is hoping to use its influence to prevent substantial price hikes that could bring criticism on the new system and incumbent Democrats. Commissioners declined to predict what insurers will do when it comes to premiums for 2015, but they emphasized that they would only accept "appropriate" increases.
"We as state insurance regulators take that responsibility of our job very seriously," said Hamm on a call with reporters.
"We analyze those rate increase requests from companies in a very thorough manner, and we only approve rates that are actuarially justified."
He added that regulators must balance the interests of consumers against the interests of insurers.
Vice President Biden, Health and Human Services Secretary Kathleen SebeliusKathleen SebeliusObama's health secretary to be first female president of American University Leaked email: Podesta pushed Tom Steyer for Obama’s Cabinet Romney: Trump victory 'very possible' MORE and Centers for Medicare and Medicaid Commissioner Marilyn Tavenner attended the meeting on Thursday, Hamm said.
Other participants reportedly included Obama chief of staff Denis McDonoughDenis McDonoughObama's chief of staff joins foundation with focus on jobs Chicago mayor visits White House to meet with Trump aides Obama staffers challenged to WH scavenger hunt on final day MORE, senior adviser Valerie Jarrett and chief healthcare aide Phil Schiliro.
— This story was updated at 2:46 p.m.