Four-Year Bull Market Nears Milestone as AI Spending Sustains Rally, But Yield Risk Looms

What’s happening

The U.S. stock bull market is approaching its fourth anniversary, driven primarily by artificial intelligence spending and tech sector dominance. Historically, bull markets that survive past their fourth year tend to persist, but rising bond yields and energy price volatility pose near-term headwinds to the rally's momentum.

Market impact

Tech and mega-cap AI beneficiaries remain supported by structural growth narratives, but yield-sensitive sectors face rotation risk if Treasury yields spike further. Truist Advisory Services notes that longevity of bull markets past year four historically favors continued upside, but execution risk on earnings remains high.

Broader implications

Sustained AI capex cycles could extend the bull market, but macro headwinds—geopolitical conflict, energy shocks, rate volatility—threaten to derail the narrative. Market breadth and earnings quality will determine whether this becomes a fifth-year bull or a correction catalyst.