Irrational exuberance - Wikipedia
"Irrational exuberance" is the phrase used by the then-Federal Reserve Board chairman, Alan Greenspan, in a December 1996 speech given at the American Enterprise Institute during the dot-com bubble of the 1990s. The phrase was interpreted as a warning that the stock market might be overvalued.Nvidia closes in on $4 trillion valuation, surpasses Apple's record | TechSpot
"According to LSEG data, Nvidia's current valuation now exceeds the combined market capitalization of all publicly listed companies in Canada and Mexico, and even surpasses the total value of all publicly traded firms in the United Kingdom."