The influence that fewer stocks, particularly tech stocks, have on U.S. markets has been growing as large-cap stocks begin to widen the gap with smaller stocks. As investments in vehicles that track the performance of the S&P 500 are ever more popular, the situation creates shaky ground for investors. U.S. equity performance hinges on a less diversified group of stocks.
Sources: Bloomberg LP; FTSE International; P&I Research Center
Compiled and designed by Charles McGrath and Gregg A. Runburg