GameStop shares surged at Monday's opening bell after the trader Keith Gill, who posts on social media under the aliases "Roaring Kitty" and "DeepFuckingValue," appeared to disclose a $116 million ...

Keith Gill, the trader known as Roaring Kitty who helped launch GameStop meme mania, is back online. But his original bull case on GameStop didn’t exactly pan out.

GameStop opened at $40.19 Monday morning, up from $23.14 at Friday’s close. The videogame retailer’s rally has since cooled off a little, but Gill’s position remains hefty.

If it is Gill making these posts, it’s unclear how he’s funding the bets if not through his prior GameStop profits. He hasn’t made a video on his Roaring Kitty YouTube channel discussing his ...