The nation’s largest hospital operator HCA Inc., announced on Monday that a private equity group has bought the company for about $21 billion. The firm has been struggling due to an increase in competition and in addition to growing unfunded liabilities.

The private equity group consisting of Bain Capital, Kohlberg, Kravis Roberts & Co., and Merrill Lynch, according to the Wall Street Journal will also assume HCA’s debt of $10.6 billion bringing the deal close to $31.6 billion.

Doctor’s practices along with unpaid hospital bills have been cutting into HCA’s profit margins. In the second quarter earnings report for 2006, HCA missed Wall Street estimates where it recorded a net profit of $295 million or $0.72 EPS compared to the $0.77 estimate by Thomson First Call.

Jack O. Bovender, Jr., HCA Chairman and CEO, said that the new equity group will still maintain the HCB belief in putting patients first.

“We are very pleased to have an experienced group of investors who are committed to maintaining our company's culture of a patients-first approach to high quality, compassionate care,” Bovender Jr. said.