Einhorn's Greenlight Capital sees down month in July: Source

David Einhorn, founder of Greenlight Capital.
Adam Jeffery | CNBC

One of the hedge-fund industry's most respected stock pickers, David Einhorn, struggled in July, with his flagship Greenlight Capital LP fund dropping 6.1 percent, according to a person who reviewed his figures.

The downbeat performance left Einhorn's fund down 9 percent year-to-date.

Given that stock markets have mostly rallied of late, the exact sources of Greenlight's pain weren't entirely clear. Yet two of its larger long positions, according to filings, were down substantially: Consol Energy, which dropped 24 percent; while SunEdison, another energy company, tumbled 22 percent.

Public filings, however, typically don't reveal an investor's short, or bearish, positions—an area in which Einhorn tends to be active.

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Broadly speaking, Greenlight's shorts could have been harmed by a modest stock-market rally, which pushed the S&P 500 Index up nearly 2 percent for the month. Still, one of the stocks Einhorn has been most bearish about of late (even though he hasn't explicitly said his fund is short it), is Pioneer Natural Resources.

The shale driller is one Einhorn nicknamed "the MotherFracker," and it fell on the month.