Einhorn: Here's what I'm still long and short

David Einhorn, president of Greenlight Capital.
Katie Young | CNBC
David Einhorn, president of Greenlight Capital.

Widely followed hedge fund manager David Einhorn reiterated his belief in two existing positions at an investment conference Tuesday: A short bet against Athenahealth and a long play in AerCap, according to a person who witnessed the presentation.

The remarks were made at an event hosted by Grant's Interest Rate Observer in New York. A spokesman for Einhorn's Greenlight Capital declined to comment.

Athenahealth stock declined about 2.8 percent in morning trading and had been down more than 4 percent at one point. AerCap was up about 2.6 percent at the same time.

Einhorn recommended shorting Athenahealth at the Sohn Investment Conference nearly a year ago. He called the company part of a "basket" of "bubble stocks" he was shorting. The presentation from that event is now posted on the Greenlight website.

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Greenlight's top positions as of Dec. 31 are Micron Technology, Apple, SunEdison, Consol Energy and Marvell Technology, according to a public filing.

CNBC previously reported that Greenlight's main fund is down 1.8 percent net of fees for the first quarter.