Over 400% of GDP: top analyst finds corporate equity double the level from the dotcom bubble — and triple 1987’s Black Monday

America’s stock market has swollen to a size that dwarfs every valuation extreme of the past four decades, according to JPMorgan Asset Management’s chief global strategist — a warning that dropped just days after a separate McKinsey study found the world’s wealth is increasingly decoupled from real economic growth. On Aug. 10, David Kelly calculated that “the market value of all U.S. corporate equity is now over 400% of GDP.” That compares with 244% just before the pandemic, 204% at the peak of 2000’s dotcom bubble, and 74% before the 1987 stock market crash known as Black Monday. If it sounds familiar, that’s because Kelly’s metric is almost like the famous Buffett Indicator — the ratio of the total value of publicly listed U.S. companies to GDP — but it’s a bit broader, covering all U.S.