"I'm going to take a break for now," Cohen said on Twitter late on Friday, citing "personal threats." His account no longer appeared on Saturday, and a spokeswoman for Cohen's Point72 Asset Management confirmed it was closed.

The small investors, connected on social media, mobilized to take on institutional short sellers of GameStop and other shares, sparking a short squeeze that sent those stock prices surging. The details of Cohen's holdings were not disclosed, so it was unclear if he was a short seller.

However, Cohen's Point72 and Citadel LLC gave a capital infusion to Melvin Capital, a fund that held a large short position in GameStop, enabling it to close out that position with a large loss and survive.

Cohen, who previously used Twitter largely to engage with fans of the New York Mets baseball team after he bought a majority stake last year, was among fund managers who received threats as the GameStop saga unfolded.

On Thursday, Cohen got into a heated debate with blogger Dave Portnoy, who founded the sports and pop culture blog Barstool Sports. Cohen, worth roughly $14 billion, tweeted, "Hey Dave, What's your beef with me. I'm just trying to make a living just like you."

Point72 lost between 10% and 15% in value since the start of the year to the middle of the week, people familiar with the numbers said.

(Reporting by Svea Herbst-Bayliss; Editing by Cynthia Osterman)

By Svea Herbst-Bayliss