Federal Reserve distribution data put nearly nine-tenths of U.S. corporate equities and mutual funds in the hands of the wealthiest tenth of households in 2021. The Fed’s distributional accounts are the place to check the series, which is about ownership of those assets, not ownership of every business in the economy.
The number bothered me because market gains do not reach households evenly. Encouraging more people to buy stocks doesn’t erase the gap when many households have little spare income to invest. I would look at both who owns the assets and how much of each household’s wealth depends on them. A rising index can be good news while doing very little for the people with no stake in it.