Is it true: GameStop short squeeze (Jan 2021)?

There's no solid evidence for it.

Unsubstantiated. The events around the claim are documented: the squeeze, Melvin Capital's losses, the $2.75 billion Citadel and Point72 investment in Melvin announced on January 25, 2021, and Robinhood's January 28 buying restriction, which hurt retail investors. The claim that Citadel or hedge funds directed that restriction has not cleared the evidence bar. Robinhood's CEO, Citadel's Ken Griffin and Melvin's Gabe Plotkin each denied it in sworn testimony on February 18, 2021. The House Financial Services Committee majority staff report (June 2022) documented a roughly $3 billion collateral deficit that Robinhood faced that morning and cited no Citadel instruction; the SEC staff report (October 2021) described the broker restrictions as a reaction to clearinghouse margin calls and cited no evidence of hedge-fund pressure, though it made no separate finding on the allegation. A federal district court dismissed the investors' antitrust conspiracy complaint on November 17, 2021 (with leave to amend) and again on May 12, 2022, calling the pleaded Robinhood-Citadel emails 'vague and ambiguous'; the Eleventh Circuit affirmed on June 26, 2024 on a different ground, without deciding whether a conspiracy had been plausibly alleged. No court has tested the claim at trial.