AI investment in US could reach $9 trillion by 2032 amid profitability doubts

Columbia professor Stijn Van Nieuwerburgh estimates total US AI investment could hit $9 trillion by 2032, equal to 3.2% of annual GDP. WSJ columnist James Mackintosh compared the boom to the 1840s railway bubble and the dot-com fiber buildout, warning much capital may not be recovered.

• US AI investment could reach $9 trillion by 2032
• That equals 3.2% of annual US GDP
• Nvidia's forward PER fell from 23 to 15 even as shares rose 15%
• Capex of the five largest hyperscalers to exceed $1.2 trillion next year