President Joe Biden aims to expand access to health care by proposing changes to the Affordable Care Act that would make more people eligible for premium tax credits to buy ACA marketplace plans.

The Treasury Department proposal would allow families to receive tax credits if their coverage costs exceed more than 10 percent of their incomes, a senior administration official told reporters.

The change, scheduled to take effect in January, would allow 200,000 uninsured people to gain coverage and lower premiums for a million others, the official said.

“We think it’s the most significant administrative action to improve the implementation of the ACA,” the official said.

The official declined to say how much it would cost to fix the so-called family glitch or how it would be paid for.

Under the current system, costs for single people on coverage plans are capped at 10 percent of their incomes, but that doesn’t apply to spouses and children who are offered insurance through family members’ jobs. That means those family members are sometimes paying 25 percent or 30 percent of their incomes on health insurance, the official said.