Nvidia's order book could collapse if its biggest customers cut AI spending, much as Cisco fell 90% in 18 months after the 1999 infrastructure boom. Microsoft, Google, Amazon and Meta are spending $650bn on AI infrastructure this year, which is effectively Nvidia's whole business model. If their CFOs find in Q3 that AI capex is not producing measurable returns, they cut, Nvidia's orders fall and so does 30% of the S&P 500. Timing is the only question. x.comÂ

