Shares of GameStop shot up 400 percent last week, egged on by the Reddit forum r/WallStreetBets. The online community rallied to drive up the stock price and put the squeeze on big hedge funds who had bet against the struggling video game retailer. Reddit chief executive Steve Huffman — who calls  r/WallStreetBets one of his “guilty pleasures” — described this as “the online stock-betting equivalent of, like, jumping off a cliff into a river.”

On this episode of “Sway,” Kara speaks to Huffman about the ethos behind the online movement, whether Reddit may have been used for market manipulation and if he fears an investigation by the S.E.C. She also presses him on the narrative that this is a David vs. Goliath story of Main Street beating Wall Street — after all, who will be left holding the bag when GameStop’s stock eventually comes crashing?

You can find transcripts (posted midday) and more information for all episodes at nytimes.com/sway, and you can find Kara on Twitter @karaswisher.