https://techcrunch.com/2021/01/28/the-somewhat-boring-reason-it-appears-that-robinhood-yanked-trading-on-some-securities/

After enduring a day’s worth of taking a beating across social media, government, and the various app stores of the mobile world, Robinhood took to its own blog and CEO’s Twitter account to explain why it had halted trading of some stocks earlier today.

That Robinhood had restricted trading in a number of securities was bombshell news after the consumer trading platform had become synonymous with not only a rise in retail investing, but also a risky wager by some individual investors to push shares of heavily-shorted companies, including GameStop, AMC and others higher. Speculation that Robinhood was limiting the trading ability of those users at the behest of, pick your poison, Citadel, the US government, hedge funds, Janet Yellen, or others, ran rampant.