Robinhood contracts with Wall Street heavies to fill these trades, I would guess somebody big made some calls yesterday https://twitter.com/jbillinson/status/1354782468721823745?s=19

NB that Citadel Securities, who fills the order flow for Robinhood, and Citadel the hedge fund that bailed out Melvin, are different companies (though Ken Griffin founded both of them) https://www.theverge.com/22251427/reddit-gamestop-stock-short-wallstreetbets-robinhood-wall-street

anyway the whole point of Robinhood is for Wall Street to swindle naive retail investors by getting ahead of their orders. that's why Citadel Securities pays a huge premium to do it https://www.cnbc.com/2020/08/13/how-robinhood-makes-money-on-customer-trades-despite-making-it-free.html

and that probably is how it works, on average, most of the time! people have lost their shirts gambling on there https://www.nytimes.com/2020/07/08/technology/robinhood-risky-trading.html

and now we see if the little guys actually figure out some tactic to beat the hedgies at their own game, the big money will conspire to prevent it from happening. the table is tilted folks https://theweek.com/articles/963396/gamestop-makes-case-financial-regulation