The artificial intelligence stock trade that powered much of Wall Street's recent rally is now sending sharply contradictory signals, leaving investors to parse a market that can surge and crater within days.

A fresh wave of selling in AI-linked shares knocked the broader U.S. market back to levels last seen five weeks ago, according to reporting by The Hindu Business Line. The downturn prompted what Yahoo Finance described as Wall Street weighing "the dark side of AI" — the fear that the technology will disrupt industries and corporate earnings before it creates new ones.

Alphabet, Google's parent company, was among the notable casualties. According to Yahoo Finance, shares of Alphabet slipped on investor concerns over rising capital expenditures and uncertainty around whether the company can effectively monetize its AI investments — a tension playing out across the sector.

Another unnamed AI stock that had appeared on track for a $1 trillion market valuation has since lost that momentum, according to AOL.com, illustrating how quickly market enthusiasm can fade.

Yet the picture is not entirely grim. Wall Street opened higher in subsequent sessions as AI stocks clawed back some ground and oil prices eased, per KOB.com — a reminder of how volatile the sector has become.

Underpinning all of this is a structural concern flagged by MSN: U.S. technology stocks, fueled by AI enthusiasm, now account for more than 39% of the S&P 500's total market capitalization. That level of concentration means a stumble in a handful of mega-cap tech names can ripple through the entire index.

The whiplash matters because millions of ordinary investors hold these stocks through index funds — what happens to AI megacaps no longer stays on Wall Street.