Think Nvidia looks dear? American shares could get pricier still

And so to a sell signal fit for 2024: Keith Gill is back on social media. Mr Gill was an architect of the meme-stock frenzy of 2021, exhorting retail traders to buy shares in GameStop, a struggling chain of video-game shops. After a three-year absence he is posting once again, now apparently in possession of a stake in the firm worth a few hundred million dollars. GameStop’s share price has resumed a gut-churning rollercoaster ride and is up by more than 40% since Mr Gill’s return; the ailing company has made use of the excitement to issue some $3bn-worth of new shares. If you are looking for signs of speculative excess in markets, this is Exhibit A.