Here's a March 2023 update of Hendrick Bessembinder's work published in 2018 showing that a very high fraction of all wealth creation has come from a small number of stocks. The original work covered data back to 1926; the update covers the period 1990- 2020.

"Abstract:
We study long-run shareholder outcomes for over 64,000 global common stocks during the January 1990
to December 2020 period. We document that the majority, 55.2% of U.S. stocks and 57.4% of non-U.S.
stocks, underperform one-month U.S. Treasury bills in terms of compound returns over the full sample.
Focusing on aggregate shareholder outcomes, we find that the top-performing 2.4% of firms account for
all of the $US 75.7 trillion in net global stock market wealth creation from 1990 to December 2020.
Outside the US, 1.41% of firms account for the $US 30.7 trillion in net wealth creation."

file:///Users/danielroberts/Downloads/SSRN-id3710251.pdf

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