That could have a profound impact on the many Americans who now get coverage through their jobs -- sending them out to buy their own coverage instead.

“It has the potential to transform employer-provided health insurance in a major way,” Levitt said in an email. If the projections are accurate, that would represent “a huge influx” of workers into the individual market governed by Obamacare rules.

Meaningful Change
A broad shift to HRAs could resemble the movement in retirement benefits from defined benefit pensions to 401(k) plans, where employers make fixed contributions instead of promising a set benefit for years in the future. A similar change in health coverage would give businesses more predictable costs, while shifting the risk of higher health-care expenses onto workers.

“The rule will provide hundreds of thousands of businesses a better way to offer health-insurance coverage, and millions of workers and their families a better way to obtain coverage,” Joe Grogan, director of the White House Domestic Policy Council, told reporters on a conference call Thursday.

While it may be years before the full consequences of more flexible HRA rules become clear, other effects of Trump’s executive order are already apparent.

The biggest impact so far comes from the rule expanding access to short-term health plans. While the plans are cheaper than Obamacare coverage, they cover less and can exclude people with pre-existing conditions.

Federal actuaries estimated last year that an additional 600,000 people would buy such plans in 2019. That could drive premiums up in the ACA markets, but many people purchasing Obamacare coverage are insulated from hikes.

Congressional Democrats have criticized short-term coverage as “junk” and are probing several companies that sell it.

Another Trump administration rule to encourage small businesses to jointly buy insurance through business associations has been held up by a court challenge, with a federal judge calling it “an end-run around the ACA.”

Beyond executive actions, the Trump administration is also pursuing its health-care agenda in the courts. A Texas judge ruled late last year in favor of GOP-controlled states that argued the Affordable Care Act was unconstitutional. That ruling is being appealed by Democratic attorneys general.