As the Securities and Exchange Commission begins looking into last week’s wild surge in GameStop stock, it’s investigating social media for signs of fraud, Bloomberg News reports. It’s not clear which social media platform the SEC is investigating, but the surge originated on the Reddit forum r/WallStreetBets, where users mass-bought GameStop stock, along with several other companies that Wall Street firms were betting against, such as AMC and BlackBerry. According to Bloomberg, some Wall Street insiders believe the charge “might have also involved professional investors who either took advantage of the Reddit-fueled frenzy or helped hype it.”