PORTLAND — American Skiing Co., saddled with $400 million in debt, announced Monday that an investment group will give it $150 million in exchange for nearly half the company.

The cash infusion from Oak Hill Capital Partners will help reduce debt and give the resort operator access to capital after a dismal ski season, said Skip King, company spokesman.

“The difficult season was certainly a factor” in pursuing the investment deal, he said.

The deal will help the Newry-based company develop its resort villages at its nine ski areas across the country.

“This investment stabilizes our capital structure and provides the company with substantial liquidity,” said Leslie B. Otten, chairman and chief executive officer.

Oak Hill will purchase $150 million in preferred stock in American Skiing. At the close of the transaction, Oak Hill’s investment will represent a 48.5 percent stake in the company, becoming the ski company’s largest single shareholder. The ski company’s senior management will control 26.7 percent in the restructured group.

The investment group will appoint four members to the 11-member board and Otten can appoint another four, King said.

“They are participating at the board level,” King said. “It’s an investment company, not an operational company, and they have made it clear that they have a lot of confidence in our management team. Our management team will remain unchanged.”

“It’s an interesting and good opportunity with good management and a lot of potential,” said Hollis Rafkin-Sax, spokeswoman for Oak Hill. “We’re hoping it has a very promising future.”

Otten said last month that American Skiing has $400 million in debt, but he is confident in the future of the business.

The financial troubles haven’t forced American Skiing to sell any of its nine resorts. But the company is selling some of its “non-strategic” assets, such as the Sugarbush Inn and golf course in Vermont. The company jet also is grounded and staff at some of the resorts has been reduced.

This is the third investment for Oak Hill, a $1.6 billion private equity partnership based in New York and Menlo Park, Calif.

The transaction, subject to regulatory approval and consent from senior lenders, is expected to close before the end of August.

American Skiing operates ski, snowboard and golf resorts in the United States, including Sugarbush, Killington and Mount Snow in Vermont, Sunday River and Sugarloaf USA in Maine, Attitash Bear Peak in New Hampshire, The Canyons in Utah, Steamboat in Colorado and Heavenly in California-Nevada.