Hilton Worldwide files for an I.P.O.

Hilton Worldwide Holdings, the hotel company owned by the Blackstone Group, filed for an initial public offering on Thursday, seeking to raise at least $1.25 billion in what will be one of the most closely watched I.P.O.’s of the year.

Though details of the offering were not yet available, Hilton could be valued at about $30 billion once it goes public, capping a remarkable turnaround for what was once considered one of the worst deals of last decade’s private equity boom.

Blackstone took Hilton private in 2007, paying $26 billion for the company, which is based in McLean, Va. The deal was among those that came to symbolize the outsize ambitions of buyout shops in the years before the financial crisis as firms including Blackstone went after ever-larger targets.

Hilton did not disclose the precise sum it was looking to raise, or at what price it intends to price shares. But Blackstone does not intend to issue so many shares that it loses control of Hilton. Instead, the private equity firm will continue to own a majority of the voting shares, allowing it to control the makeup of the board.

With comparable hotel chains like Starwood and Marriott trading at about 12 times earnings before interest, taxes, depreciation and amortization, and Blackstone growing at a healthy clip, its valuation could be about $30 billion by the time shares are likely to start trading early next year.

Over the last six years, Blackstone has managed to turn Hilton around, making it an increasingly dominant force in the global hotel market. Revenue in 2012 was $9.3 billion, up 15 percent from 2010.

Adjusted earnings before interest, tax, depreciation and amortization were $2 billion in 2012, up 25 percent from 2010.

According to its filing with the Securities and Exchange Commission, Hilton has increased the number of open rooms in its system by 34 percent, to 170,000. That amounts to 4.5 percent of all hotel rooms globally, according to Smith Travel Research.

The company is also continuing to expand. It is responsible for 18 percent of global rooms under construction. In addition to Hilton brand hotels, the company operates the Waldorf Astoria, Conrad, DoubleTree and Embassy Suites brands.

Hilton has achieved its growth by doubling down on its strategy of licensing the Hilton brand to franchisees around the globe. These properties, owned and managed by other operators, which pay Hilton a franchise fee, are more profitable than the hotels owned and operated by Hilton itself.

The main underwriters for the I.P.O. are Deutsche Bank, Goldman Sachs, Bank of America Merrill Lynch and Morgan Stanley.