Ken Griffin warns of AI bubbles, questioning demand behind the infrastructure boom

AI can deliver useful work while the investment surrounding it becomes a bubble. That was the warning from Citadel founder Ken Griffin in an October 20, 2026 interview with Bloomberg’s Dani Burger. He questioned future infrastructure demand and said businesses have been uneven in turning expensive AI models into value.

Speaking at Citadel’s Future of Global Markets Conference, Griffin described speculative excess as a familiar companion to economic transformation. His warning was not a rejection of AI’s potential: he also argued that companies surviving a technology bubble can become market leaders for decades, according to The Hill.

Useful tools still have to earn their bills

Griffin put the immediate challenge in terms of customers’ bills from Anthropic and OpenAI. He said companies were asking how to ensure that spending produced productivity.

He offered an example from inside Citadel. AI agents had cut some sophisticated research tasks from weeks to hours, he said, according to 24/7 Wall St.

The danger of building more capacity than customers need

Griffin’s infrastructure concern was about investing enormous sums before future demand is clear. He compared graphics processing units, or GPUs—the chips used to run AI systems—to airline seats. If available capacity exceeds demand, operators may cut prices because the additional cost of serving another customer is relatively low, 24/7 Wall St. reported.

Earlier analysis published by Brookings puts the potential buildout at $10.3 trillion for AI data centers, power and chips from 2025 through 2032. Its author, Columbia Business School professor Stijn Van Nieuwerburgh, said a recession could reduce demand, tighten financing and lead to canceled projects.

Brookings also identifies a visibility problem: financing is moving into joint ventures, private credit and separate project entities, making debt harder to see from outside. Its assessment stops short of calling this a systemic risk. Instead, it calls for better measurement and disclosure while the financing structures are still taking shape.

Citadel’s holdings are a snapshot, not a rebuttal

Citadel has also participated in the companies central to AI’s expansion. A 24/7 Wall St. compilation of its reported June 30 holdings puts Amazon at $2.59 billion, Nvidia at $2.36 billion, Microsoft at $1.41 billion, and Broadcom and Alphabet at $1.1 billion each—approximately $8.6 billion combined. The share counts moved in different directions during the quarter:

• Amazon’s share count increased by 34%.
• Microsoft’s share count increased by 43%.
• Nvidia’s share count fell by approximately 37%.

The SEC filing index confirms that the amended holdings report was filed September 2 and covers June 30. The stock values therefore predate Griffin’s October remarks. The filing also disclosed call and put options, which can hedge risk or express opposing views; it does not establish Citadel’s current net exposure.