So says the LA Times, here:
And on Wednesday, Bush resigned from the board of directors of Tenet Healthcare Corp., also effective Dec. 31, according to a corporate filing. The Dallas-based company actively supported the 2010 Affordable Care Act, and has seen its revenue rise from it, an issue that could draw fire in Republican primaries.
Bush earned cash and stock awards worth nearly $300,000 from Tenet in 2013, according to corporate filings. He also sold Tenet stock worth $1.1 million that year, the records show.