Einhorn, who runs Greenlight Capital, wrote in a letter "we are in the midst of an enormous tech bubble," but noted "September 2, 2020 was the top and the bubble has already popped." Reuters saw a copy of the letter.
Einhorn said he's "adjusted" his portfolio's short-book with bets that stock prices will fall by "adding a fresh bubble basket" of mostly second-tier companies and "recent IPOs trading at remarkable valuations."
Einhorn, who made a timely call against Lehman Brothers just months before the bank collapsed, said he prematurely identified what he thought was a bubble in 2016. He announced his first bubble basket -- including bets against high flyers like Tesla and Amazon -- years ago. Now, he says, "there is a consensus that there is a bubble."
The signs are clear, Einhorn wrote, citing the race to list companies publicly, high volumes in speculative trading instruments and a "parabolic ascent toward a top."
One of the strangest signs may be a recent job application Einhorn said he had received via email from a from a 13-year old who says he quadrupled his money since February.
Einhorn did not identify the stocks he's betting against.
He does expect some stocks to keep climbing and said he added new names to the portfolio: B2B IT services company Synnex, software company NCR and sensor maker ams AG.
During the quarter, Greenlight climbed 5.9% compared with an 8.9% gain in the broader Standard & Poor's 500 index.
(Reporting by Svea Herbst-Bayliss; Editing by Alexandra Hudson)
By Svea Herbst-Bayliss