If you’re a fund manager, a bubble is a) something that has delivered sky-high returns, and; b) a thing you don’t own. Your clients are going to ask why you missed it. One good reason for not owning it is because the thing in question is in a bubble. And, well, bubbles burst.

Unusually, even people at the centre of the AI boom now say it’s a bubble. Jeff Bezos think’s we’re in a “good” type of bubble. Anthropic-backer Hemant Taneja, chief executive of venture capital firm General Catalyst, reckons “of course there’s a bubble”. And Sam Altman, OpenAI’s chief executive, responded recently to the question of an AI bubble with the soothing words: “I do think some investors are likely to lose a lot of money.”

Where does Goldman Sachs sit? Well, the most recent view of the bank’s chief global equity strategist Peter Oppenheimer is: “Not a bubble?.?.?. yet.”