BofA AI Bubble Warning Hits Dot-Com Level: Is Crypto Next?

A warning sign is flashing for investors as Bank of America's (BofA) AI bubble warning has reached Dot-Com level. According to data from BofA strategist Michael Hartnett, the AI Big 10 share of US market cap now stands at 41%, matching the 2000 dot-com peak.

Hartnett defines the AI Big 10 as the Magnificent 7 plus Broadcom, AMD, and Micron. The concentration of these stocks in the market is a concern for BofA, not a price forecast. This warning comes after ZeroHedge shared new data from BofA Global Research.

The AI bubble warning rests on exactly the link between bond yields and stock market bubble endings. BofA points out that three past episodes, each ended by a bond yield surge, had one thing in common: market concentration at 41% was the marker. These episodes include the Nifty Fifty (1973), Japan (1989), and the Dot-com bubble (2000).

The US 10-year Treasury yield has already moved quickly this week, reaching 5.18% on September 24, 2026, up from 4.96% on September 22. With roughly 0.73 points before the 2-point mark, the link between bond yields and stock market bubble endings is tightening.