London CNN  —  Shares in GameStop shot up almost 73% in pre-market trade Monday as the renewed frenzy around meme stocks shows little sign of abating. The video game retailer’s stock soared hours after a Reddit post by stocks influencer Keith Gill — also known as “Roaring Kitty” — revealed that he had bought nearly $116 million worth of the stock. The post was the first on Gill’s Reddit account in more than three years, when social media-fueled hype around GameStop (GME) shares was in full swing. Meme stocks are shares that swing wildly in value based on their popularity among trader communities on social media rather than the companies’ fundamental characteristics. The frenzy started with GameStop in 2021, extending to other companies such as AMC Entertainment (AMC) and Bed, Bath and Beyond, which has since filed for bankruptcy. The GameStop Corp. app on a smartphone arranged in Hastings-On-Hudson, New York, U.S., on Friday, Jan. 29, 2021. Tiffany Hagler-Geard/Bloomberg/Getty Images Related article GameStop, AMC shares skyrocket after meme stock trader posts on X for first time in 3 years Shares of AMC Entertainment were up nearly 28% by 6.47 a.m. ET Monday. Gill also sent GameStop shares soaring last month after posting a meme on X of a man leaning forward in a chair holding a video games console — his first post on that platform in three years. GameStop had posted a similar cartoon back in February. The meme is interpreted to mean “when things get serious,” according to website Know Your Meme. Gill was one of the main posters on the WallStreetBets subreddit — a thread where Reddit users can post on a particular topic — which drove eye-popping rises in GameStop’s stock in 2021. Retail investors bid up the shares, targeting short-sellers, who had been betting on GameStop’s stock falling. Short-sellers aim to make a profit by borrowing a particular company’s shares, selling them and returning them after purchasing them once they’ve fallen in price. In 2021, in testimony to US Congress on the GameStop mania, Gill described himself as a casual daytime trader. He also said he did not set out to help stoke the GameStop frenzy and instead believed the stock offered an attractive opportunity for investors.