GameStop short squeeze

In January 2021, a short squeeze of the stock of the American video game retailer GameStop and other securities took place, causing major financial consequences for certain hedge funds and large losses for short sellers. Approximately 140 percent of GameStop's public float had been sold short, and the rush to buy shares to cover those positions as the price rose caused it to rise even further. The short squeeze was initially and primarily triggered by users of the subreddit r/wallstreetbets, an Internet forum on the social news website Reddit, although a number of hedge funds also participated. At its height, on January 28, the short squeeze caused the retailer's stock price to reach a pre-market value of over US$500 per share ($125 split-adjusted), nearly 30 times the $17.25 valuation at the beginning of the month. The price of many other heavily shorted securities and cryptocurrencies also increased.

On January 28, some brokerages, particularly app-based brokerage services such as Robinhood, halted the buying of GameStop and other securities, citing the next day their inability to post sufficient collateral at clearing houses to execute their clients' orders. This decision attracted criticism and accusations of market manipulation from prominent politicians and businesspeople from across the political spectrum. Dozens of class action lawsuits have been filed against Robinhood in U.S. courts, and the U.S. House Committee on Financial Services held a congressional hearing on the incident.