By going private in one of the biggest leveraged buyouts ever, HCA ( HCA) has finally found a way to boost its ailing stock. Shares in the giant hospital chain rose 3.4% Monday after HCA said it plans to sell itself to a group of private investors for $51 a share in a landmark deal valued at some $21 billion. The announcement confirmed rumors that began driving HCA shares higher last week. But the announcement also comes as HCA posted another quarter of weak admissions and rising bad debt from the uninsured. And because the fundamentals remain questionable across the industry, most rival hospital chains failed to rally on the news of the big buyout. "I understand that while earnings don't matter right now, they were really pretty awful," notes Sheryl Skolnick, senior vice president of CRT Capital Management. "If you're going to report a quarter like that, you want to have some good news -- and they do." HCA expects to sell itself by the end of this year to a consortium of private equity investors that includes Bain Capital, Kohlberg Kravis Roberts, Merrill Lynch Global Private Equity and members of the Frist family, who founded the company. Indluding debt assumption, the transaction would be worth $33 billion, topping KKR's 1989 buyout of RJR Nabisco as the biggest LBO in history. Still, Skolnick says, HCA secured a higher multiple when the company went private last time around. That transaction, executed the same year as the Nabisco deal, came in the midst of a tough reimbursement environment that eventually passed and allowed the deal to succeed. But some believe that today's biggest challenges -- particularly bad debt from the uninsured -- could prove harder to overcome. Even JP Morgan analyst Andreas Dirnagl has noted some clear differences. Dirnagl has an overweight rating on HCA's stock, and his firm -- which counts HCA as an investment banking client -- owns more than 1% of the company's shares itself.