Warren Buffett Warned Investors About This Number 27 Years Ago. It's Never Been Higher. Should AI Investors Worry?

U.S. corporate profits hit 13% of GDP in Q2 2026, more than double the 6% level Warren Buffett flagged as a warning sign in 1999. That is the highest reading on the metric Buffett singled out, and it lands squarely on the megacap AI trade.

The article attributes the surge to massive AI infrastructure spending by AMZN, GOOGL, MSFT and META. Those names anchor QQQ, so a profit-share reading this elevated puts index-level earnings assumptions in focus.

Economists cited in the piece warn that the gains could prove "paper earnings." The logic: if AI spending slows, the profits it generated could disappear. Rising labor costs present a second threat, with the potential to compress margins from current levels.

Berkshire Hathaway offers a market-signal counterpoint. The company is running record stock buybacks, which the article reads as caution about current valuations. Interpretation: Buffett's firm putting capital into its own shares, rather than broad equity purchases, is consistent with a view that prices elsewhere are rich. BRK.A and BRK.B holders are effectively the beneficiaries of that discipline.