Closely followed fund manager David Einhorn, who runs Greenlight Capital, presented one of the short positions from his "bubble basket."
In his latest investor letter, he wrote about how a bunch of "cool kid" stocks made him think we're seeing the second tech bubble in 15 years. He's short a number of these companies in what he's calling the "bubble basket."
He's going to illustrate his bubble basket by talking about one company and not disclosing the others.
His short is AthenaHealth.
Shares of the stock have fallen more than 7.7% in the after-hours session.
He said it's an excellent company and has a great CEO.
He doesn't want it to fail. He just thinks it's over-priced. He thinks this stock can fall 80%.
He also said the company isn't positioned to succeed the way the bulls hope.