What's so scary about a mega-cap tech bull market?

ASU expert says if it weren't for narrow breadth in the stock market, we wouldn't have returns.

In this story published June 16, 2023, in Kiplinger:

When stated in terms of lifetime dollar wealth creation, the best-performing 4% of listed companies explain the net gain for the entire U.S. stock market since 1926, as other stocks collectively matched Treasury bills.

– Hendrik Bessembinder, Francis J. and Mary B. Labriola Chair in Competitive Business and professor of finance