The rally in the U.S. stock market, fueled by hype around artificial intelligence, is prompting comparisons with the dot-com bubble. Market participants fear that quotes are overvalued, writes Reuters.

Enthusiasm for AI, along with a robust economy and strong earnings, has pushed the S&P 500 and Nasdaq indexes upward. While investor enthusiasm hasn't reached the peaks of the dot-com era, the similarities are noticeable. A small group of stocks - Cisco, Intel, Microsoft and Dell - is now leading the way, reminiscent of the "Four Horsemen" of the late 1990s, the portal notes.

However, the rise caused by AI may end up like the dot-com boom, when the Nasdaq collapsed by almost 80% from its peak. Back then, the securities of some internet companies like Amazon managed to survive, but many have not recovered. It's unclear what will happen to AI stocks, notes Samir Samana of Wells Fargo Investment Institute, and it's unclear who the long-term winners in the sector will be.

The tech sector, according to LSEG Datastream, now represents 32% of the S&P 500, the highest since 2000. Microsoft, Apple and Nvidia represent more than 20% of the index.