Hedge fund manager David Einhorn exited Pfizer

, his largest holding, and made new bets on CBS Corp ., General Motors Co and Marvell Technology Group during the third quarter.

Einhorn made significant changes during the quarter, but that was not enough to prevent the firm, Greenlight Capital LLC, from losing a little bit of money. He is one of the industry's most successful investors, with a history of delivering double-digit returns.

Generally, our longs fell a bit more than the markets, but our shorts fell even more and our macro investments helped mitigate the loss from being net long in a declining market, Einhorn wrote to clients on Monday, telling them that Greenlight Capital LP fund had dipped 1.2 percent. Reuters reviewed a copy on Tuesday.

French chemical company Arkema was the portfolio's biggest loser during the quarter, Einhorn said. Sprint Nextel Corp also contributed to losses after reporting poor quarterly results, he added.

Most prominently, Einhorn sold about 23 million shares in drugmaker Pfizer. We exited Pfizer because much of our thesis played out, Einhorn wrote in the investor letter. He also worried about future reimbursement cuts for branded pharmaceuticals.

A year ago, Einhorn had said Pfizer shares were substantially undervalued because of investor pessimism about the company's roster of experimental medicines, but added that the new chief executive officer could brighten the prospects.

During the quarter, Einhorn also exited BP , saying his firm roughly broke even on that investment, and he liquidated a bet against hospice care provider Amedisys Inc , which had been very profitable.

At the same time he made three new bets, he said in the letter.

Einhorn's biggest holdings are now physical gold, Apple Inc , the Market Vectors Gold Miners ETF, Microsoft Corp and Vodafone .

In October, when the market rallied, Einhorn came back strong with an 8.5 percent gain that helped push the flagship fund back into the black for the year.

Greenlight sent its quarterly letter on Monday, weeks after the quarter ended and later than usual because he said he was busy working on a big presentation that detailed his bet against Green Mountain Coffee Roasters . But the letter arrived just before a critical deadline next Monday, when big investors must submit lists of their stock holdings to the Securities and Exchange Commission.

Investors of all stripes pay close attention to what hedge fund managers, who generally prefer to keep their bets out of the public eye, name on these so-called 13F filings. Similarly, all investor letters and client communications from often secretive hedge fund managers are tracked closely for clues on investment strategies.

Einhorn's Greenlight Capital manages roughly $8 billion and ranks among the more successful and prominent players in the $2 trillion hedge fund industry after having returned roughly 17.6 percent every year since Einhorn founded his firm in 1996.

A spokesman for Greenlight declined to comment.

(Reporting by Svea Herbst-Bayliss; Editing by Lisa Von Ahn)

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