AI Mania Triggers Dot-Com Bubble Flashbacks

The dot-com bubble taught investors to be wary of stock-market rallies powered by a technological boom—that is, until generative artificial intelligence sent tech stocks soaring this year.

, the graphics-chip maker at the heart of the frenzy, have nearly tripled in 2023, while the Nasdaq-100 has climbed 38% and the S&P 500 has gained 16%.

For some investors, the surge in Nvidia—now the fifth-largest U.S. company by market value—is difficult to chalk up to anything but speculative mania. Its weighting in the benchmark stock indexes means everyday investors are at the whims of its trajectory, whether they believe in AI’s potential or not.