Greenlight Capital Inc., the hedge-fund firm run by billionaire David Einhorn, plans to raise money for the first time in more than two years to take advantage of recent market turmoil.

The $10 billion firm, best known for wagering on a decline in Lehman Brothers Holdings Inc. before the bank collapsed in 2008, will begin accepting capital from existing investors on Nov. 1 and new clients on Dec. 1, according to a letter to clients yesterday that was viewed by Bloomberg News.

Einhorn, 45, whose New York-based firm has been closed to new cash since the first quarter of 2012, said two months ago that he was having difficulty finding bargains after a five-year stock rally propped up by the Federal Reserve’s asset purchases. The U.S. benchmark Standard & Poor’s 500 Index has fallen 7.4 percent from its record close on Sept. 18 as oil has sunk into a bear market and investors react to the Fed’s quantitative easing program winding down.

“While we have been fully invested for some time, it has been hard to find new opportunities,” the firm wrote. “Given the current turmoil in the markets, this is changing quickly.”

Jonathan Gasthalter, a spokesman for Greenlight with Sard Verbinnen & Co., declined to comment on the firm’s plans.

Greenlight’s main hedge fund fell 1.3 percent in September, cutting its 2014 return to 2.6 percent. That compares with an aggregate advance of 2.3 percent this year for the $2.8 trillion hedge-fund industry, according to data compiled by Bloomberg.

Third Point

The firm, founded in 1996, bets mostly on gains and losses in U.S. equities. Greenlight’s portfolio was invested 114 percent in long positions and 75 percent short at the end of September, according to a performance update.

Some other hedge-fund firms with strong track records have also been closed to new investment in recent years. Dan Loeb’s Third Point LLC, which is known for taking activist stock positions, told investors during the third quarter that it would take a limited amount of fresh capital.

Asset prices had been inflated by central-bank stimulus, Einhorn said in an August conference call for the firm’s Cayman Island-based reinsurer Greenlight Capital Re Ltd.

“As the market continues to rise in the face of conflicting economic data, global unrest and looming overdue Fed exit from quantitative easing we remain cautiously positioned,” Einhorn said.

In April, the firm said in a quarterly letter to clients that it was betting against a group of “cool kid” companies that were part of “our second tech bubble in 15 years.” The next month, Einhorn clarified that he was generally bullish on the technology industry while selling shorting a group of “momentum” stocks whose valuations had gotten out of control.

Athenahealth, Mallinckrodt

At a May 5 investment conference, Einhorn cited Athenahealth Inc., a Watertown, Massachusetts-based health-care software maker as a stock “caught up in a bubble” and predicted its shares could fall 80 percent. Athenahealth slid 14 percent the next day before rebounding to close at $120.49 yesterday in New York, down about 5 percent since Einhorn’s presentation.

In July, Greenlight said it saw an opportunity to bet against Mallinckrodt Plc, a specialty-pharmaceuticals manufacturer, if it completed its $5.8 billion takeover of Questcor Pharmaceuticals Inc. Greenlight said the deal was fueled by the availability of cheap financing rather than business fundamentals. The acquisition was completed in August.

Shares of Mallinckrodt, one of the most widely owned and shorted stocks among hedge funds, have fallen 11 percent since peaking on Oct. 6.