There's a thing called shorting a stock. You borrow the stock, sell it, then have to replace it later by a specified date. The idea being that the stock will be worth more when you sell it than when you buy it back to return to the lender. The Gamestop stock was heavily shorted. So a bunch of goons on reddit all started buying the stock, thereby raising the price, knowing full well that a lot of stock would need to be purchased to cover the shorts. That means everyone gambling on the stock sinking is losing money. And since that was mostly big-money investors, they're pissed.
I think.
