NYT:

Major stock indexes have set record after record in recent years, fueled by seemingly boundless appetite among investors for anything connected to artificial intelligence. The total value of the U.S. stock market has more than doubled over the past decade to over $75 trillion, roughly two and a half times the annual output of the entire U.S. economy, itself a record ratio.

Much of that value exists only on paper, bets on future profits that may or may not materialize in the years ahead. But the boom is supporting real economic activity today, pumping trillions of dollars of investment into semiconductor factories, data centers, power plants and transmission lines. And the wealth it is creating is helping to drive consumer spending, particularly among affluent Americans, whose appreciating stock portfolios make them more willing to shell out for luxury vacations, pricey electronics and meals at high-end restaurants.

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“The thing that has been holding everything up is the A.I. story,” said Torsten Slok, the chief economist at Apollo Global Management.

A.I. related stocks account for roughly half of the rise in the S&P 500 this year, said Adam Turnquist, the chief technical strategist for LPL Financial, adding that growth in the economy is also increasingly dependent on A.I. infrastructure spending.

“It’s becoming one big A.I. trade,” he said.

[…]

The other distinguishing factor of the current market is how concentrated it is in a handful of companies. The Magnificent Seven group of companies of Meta, Alphabet, Amazon, Apple, Tesla, Nvidia and Microsoft account for roughly a quarter of the value of all publicly listed stocks in the United States.

Now ask yourself, What is the meaning of life?