This is the biggest threat to the AI-powered bull market

The AI-driven rally has leaned heavily on blockbuster earnings growth, which helped power stocks higher in 2026. The concern now is that this engine may stall in 2027. When market gains rest on expectations of continued profit acceleration, any slowdown in that growth removes a key support—even if absolute earnings remain healthy.

For investors, the takeaway is less about predicting a specific outcome and more about understanding what the market is pricing in. Valuations tied to future earnings growth are sensitive to changes in the pace of that growth, not just its direction. A stall would not necessarily mean declining profits, but it could force a reassessment of how much investors are willing to pay for those profits.

What to watch: forward earnings guidance from major AI-linked companies, signs that capital spending is translating into realized revenue, and whether analysts begin revising 2027 estimates lower. These signals matter because they shape expectations before they show up in reported results.