Vanguard Health Systems on Friday afternoon filed paperwork with the Securities and Exchange Commission for an initial public offering of its common stock.

According to its preliminary prospectus, the hospital company plans raise $600 million with the offering, using the proceeds to pay off senior discount notes due February 2016. Any remaining net proceeds will be used for general corporate purposes, including mergers and acquisitions.

The IPO announcement follows a period of brisk acquisition activity by Vanguard, which now owns 26 facilities after snapping up eight-hospital Detroit Medical Center at the start of the year. The buying binge has, however, added to the company’s debt load. In fact, the 10.375 percent senior discount notes it is plans to redeem with IPO proceeds were issued in January.

Vanguard’s filing does not yet indicate how many shares it plans to sell or at what price range. But it says the company will continue to be a “controlled company” under New York Stock Exchange rules because its three main shareholders — The Blackstone Group, Morgan Stanley Capital Partners and members of the management team — will continue to own a majority of its stock. 

The “controlled company” distinction means Vanguard won’t have to comply with certain corporate governance requirements. Vanguard plans to take advantage of the exemptions, and so will not have a majority of independent directors on its board, its nominating and corporate governance committee and compensation committee will not consist entirely of independent directors and will not be subject to annual performance evaluations. As such, stockholders “will not have the same protections afforded to stockholders of companies that are subject to all of the corporate governance requirements of The New York Stock Exchange.”

Vanguard's IPO would be the sixth of a Middle Tennessee company since August of 2009. Preceding it during that run are Cumberland Pharmaceuticals, Emdeon, Dollar General, Noranda Aluminum and HCA. In addition, Medquist Holdings, which a year ago acquired Spheris, went public before formally moving its headquarters to Cool Springs.