" From January 1926 through December 2025, just 46 stocks—out of 29,754 common stocks listed on the public U.S. stock markets over that period—accounted for half of the $91 trillion in net wealth creation, according to a study published in March titled “One Hundred Years in the U.S. Stock Markets.” Worse, the median buy-and-hold return for all those stocks was minus 6.9%.

The study’s author, Hendrik Bessembinder, a professor of finance at Arizona State University’s W.P. Carey School of Business, calls people’s reaction to his findings a “Rorschach test” of their investment styles. “For the large majority of investors, the evidence just strengthens their view about the desirability of a well-diversified, low-cost portfolio without a lot of trading,” he tells Barron’s. “My evidence says if you pick 10 stocks at random, most likely you’re going to underperform.”