Fidelity Timmer: AI High-Yield Bonds Under Pressure; Bubble Risk Lies in Debt Rather Than Stock Valuations

Fidelity Global Macro Head Jurrien Timmer (@TimmerFidelity) posted on X that high-yield data center bonds suffered a sharp pullback last week, sparking market concerns over the outlook for AI infrastructure development. Timmer contrasted the current AI boom with the price action of the 1998–2000 internet bubble, highlighting that the key difference is that corporate earnings are currently robust while equity valuations are actually declining, whereas in 1999, stock price appreciation vastly outpaced earnings growth. However, he noted that certain segments of the credit market are sending divergent signals, suggesting that if a bubble exists, it is more likely forming on the debt side rather than in equity valuations—an early warning dynamic that similarly emerged from credit markets during the dot-com era. Meanwhile, AI-linked investment-grade bonds remain resilient, backed by the strong fundamentals of major cloud providers. Timmer indicated that the recent softness in high-yield AI debt could represent a market "clearing," which need not necessarily be detrimental to broader market conditions.