For quite some time I have had a suspicion that it was the wealthy that owned most of the stock since they derived most of their wealth (income?) from stocks. And every once in a while I would see something that would sort of depict who owned stocks: wealthy individual owners, hedge funds, mutual funds, pension funds, and other types of funds. But I couldn't get at the makeup of those "funds" - did the average person get much from those funds. Hedge funds were participated by wealthy individuals so the average person wouldn't be participating here. Pension funds are a dying breed; most people are not offered pension funds through their work. The other funds I have no idea, so it was in those funds that the average person could participate, although I doubted it.
In the discussions about the new tax plan that has been passed by Congress, Paul Krugman had some followers telling him that the average person will benefit from the new tax plans because of participation in stock ownership. Paul Krugman then tweeted a graphic rebutting that rosy view: the graphic of the distribution of ownership shows only 7% of the average population are getting the benefits from stocks. So my suspicions have been confirmed.
To the right is the graph I saw in Paul Krugman's Twitter.