Cisco’s John Chambers lived through the dot-com crash. He says the AI bubble is harder to navigate

Cisco’s John Chambers lived through the dot-com crash. He says the AI bubble is harder to navigate

By Diane Brady
Publication Date: 2026-04-20 10:04:00

  • In today’s CEO Daily: Diane Brady interviews John Chambers, who knows bubbles, about the AI boom.

  • The big leadership story: Kalshi and the SCOTUS case that could determine the future of gambling.

  • The markets: Down in Europe as tanker attacks threaten a fragile ceasefire.

  • Plus: All the news and watercooler chat from Fortune.

Good morning. Are we in a stock market bubble? If you go by the so-called Buffett Indicator, as my colleague Shawn Tully reminded readers in this piece yesterday, the answer is yes. The ratio of total stock market capitalization to GDP now stands at 232%, exceeding 1999 levels and the 200% threshold where Buffett said investors were “playing with fire.”

But is today’s bubble comparable to what we saw during the dot-com boom from 1995 to 2000? For insight on that, I spoke yesterday with John Chambers, who was CEO of Cisco from 1995 to 2015. Under his watch, it became the most valuable company on earth, with a market cap of $576 billion…