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

Blockbuster earnings growth has been a key driver of the stock market's advance in 2026, particularly among companies tied to artificial intelligence. The concern now is whether that momentum can carry into 2027. According to the source summary, the engine that has powered the rally may stall next year—framing decelerating earnings growth as the biggest threat to the AI-driven bull market.

The mechanism matters more than the headline. Equity prices reflect expectations about future profits, so a market that has risen on strong earnings is sensitive to any sign that growth is slowing. If AI-related earnings expansion loses pace, the valuation support underpinning the rally could come under pressure, and investors may reassess how much of the AI story is already priced in.

What to watch: forward earnings guidance from major AI-linked companies, revisions to 2027 profit estimates, and whether capital spending on AI infrastructure continues to translate into earnings. A slowdown in growth rates—not necessarily an outright decline—would be the signal that the market's central assumption is being tested.