Earlier this year, struggling businesses GameStop (NYSE: GME) and AMC Entertainment Holdings saw their stock prices skyrocket overnight, thanks to a short squeeze initiated by a group of investors on Reddit.com.

It was r/wallstreetbets, a coalition of largely amateur investors, that created a surge of interest in a number of stocks being shorted by some of Wall Street’s largest hedge funds.

Max Tillman looks back at this moment of financial activism.