Greenlight's David Einhorn: We're adding shorts

Investors driving back into GM stock

If corporate earnings are cooked, so is the market.

That's how billionaire investor David Einhorn is betting on stocks—a view that has lost his hedge fund firm Greenlight Capital money so far this year.

"All told, there is a good chance earnings will actually shrink this year," Greenlight's most recent letter to investors said. "We think the market is too high if earnings have, in fact, peaked for the cycle, and we have reduced our net exposure by adding more shorts."

The letter did not list new short positions. Einhorn recently told a conference audience that he was still betting against Athenahealth.