What if the AI stockmarket blows up?

Sep 7th 2025|8 min read

Since the release of ChatGPT in 2022, the value of America’s stockmarket has risen by $21trn. Just ten firms—including Amazon, Broadcom and Nvidia—account for 55% of the rise. All are riding high on enthusiasm for artificial intelligence, and they are not the only ones. Larry Ellison briefly became the world’s richest man, after AI enthusiasm prompted the share price of Oracle, his firm, to leap. In the first half of the year an IT investment boom accounted for all America’s GDP growth; in the year to date a third of the West’s venture-capital dollars have gone to AI firms.