The AI spending boom can’t last. The harder question is when it ends, and Ben Carlson’s answer is an uncomfortable one: in past booms, stock markets have tended to peak before the capex spending slows. By the time the big spenders pull back, the market has already moved on.
Carlson writes A Wealth of Common Sense, and this piece is a calm look at one of the largest concentrated bets in history. Hyperscalers worth somewhere between $22 and $25 trillion, tangled together by business arrangements, all pouring money into AI infrastructure. They have told investors that going too small is a bigger risk than going too big. And the funding has shifted from cash flow to debt.
The detail that stuck is the counterargument he refuses to ignore. Nvidia’s forward price-to-earnings ratio has fallen to a decade low, because profits have grown faster than the share price. That is not how a classic bubble usually looks.
His conclusion is refreshingly honest, and I won’t spoil it. Read it.
The Biggest Risk Everyone Already Knows About - Ben Carlson, A Wealth of Common Sense, October 2026