Having had some time to digest the Supreme Court's ruling on the Affordable Care Act, investors seem to have grown even more enthusiastic about the prospects for hospital operators. Most names in the sector are up in early Friday trading, none more so than leader HCA Holdings. After adding some 11 percent Thursday, the stock (Ticker: HCA) is up another 5 percent. That lifts to $1.9 billion the market cap gain since Wednesday's close.