Former Florida governor Jeb Bush is stepping down from the board of a hospital chain that's benefited from the 2010 federal health-care law opposed by his party. (AP Photo/Susan Walsh, File)

The for-profit hospital chain Tenet Healthcare announced on Christmas Eve that Jeb Bush would be stepping down from its board of directors by the end of the year. Bush, who has served on the board of Tenet since 2007, is starting to cut his business ties as he explores a run for the 2016 Republican presidential nomination. And there's one obvious reason why keeping Tenet on his resume might not look so good politically: Tenet has benefited greatly from the Affordable Care Act, which much of the GOP base is still committed to repealing.

Bush is giving up a lucrative board post. He earned $128,500 in cash plus $170,000 in stock last year for a total of $298,500 according to Tenet's 2013 proxy statement.

And he sat on the board during a particularly profitable time for Tenet.

Tenet is the country’s third-largest publicly traded hospital chain, with 80 hospitals across 14 states and more than 200 outpatient centers in 16 states. The Dallas-based hospital chain immediately reported reaping the benefits of Obamacare’s coverage expansion since it took effect at the start of this year.

The hospital chain’s share of uninsured patients and charity care patients has dropped significantly, while the share of Medicaid patients has increased. In just the second quarter this year, Tenet saw unpaid care drop $78 million.

This swing has been more pronounced in the five states where it operates hospitals that have opted into the ACA’s Medicaid expansion: Arizona, California, Illinois, Massachusetts and Michigan. Tenet’s also seeing more patients come in with private coverage from the Obamacare exchanges, as seen from this slide from the company’s third-quarter results issued last month.

(Tenet Healthcare)

Tenet reported third-quarter revenue was up 6 percent over the previous year, to $4.18 billion, with the company attributing 40 percent of the gain to the ACA. As you can see from this stock chart below, the company has benefited tremendously since the ACA was enacted in March 2010.

So where does Bush stand on Obamacare himself? In March 2013, the former governor of Florida urged his state not to expand Medicaid, though he bungled the facts about how the state-federal health care program for the poor is financed.

"I have doubts because I think if three years from now, as I understand it, three or four years from now, the deal is that the fed match goes from 95 [percent] back to what it is now, which is about 55 in Florida," Bush told CNN at the time. The ACA actually provides a 100 percent federal match through 2016 for the expansion population, and then the rate is scheduled to gradually drop to no lower than 90 percent.

"It's been my experience that it's been hard to tell people that once they've gotten some benefits, 'Sorry you can't have it now,'" he said in the interview.

Bush's comments came after Florida Gov. Rick Scott, a Republican, offered an emotional plea for the Medicaid expansion. But Scott never really lobbied the state legislature for it, and Florida remains one of 23 states that haven’t expanded Medicaid to all low-income adults just above the federal poverty line.