It’s no secret that a handful of tech giants have been dominating the stock market, but is it getting out of control? The top five U.S. companies — Apple, Microsoft, Alphabet, Amazon and Facebook — now make up 18 percent of the total market capitalization of the S&P 500, the highest percentage in history, according to Morgan Stanley.
Apple and Microsoft, which rose 86 percent and 55 percent in 2019, respectively, together accounted for nearly 15 percent of the S&P 500′s advance last year. The five biggies were the five biggest contributors to the S&P's gains last year; in sixth place was JP Morgan Chase, which accounted for just over 2 percent.
Apple, the largest of the five, now has its weighting in the S&P 500 larger than 4 percent. Going back to 1990, only five stocks — Apple, Microsoft, Generic Electric, Cisco Systems and Exxon Mobil — have claimed more than 4 percent of the S&P 500.