Tech’s Influence Over Markets Eclipses Dot-Com Bubble Peak

Technology companies are set to end the year with their greatest share of the stock market ever, topping a dot-com era peak in the latest illustration of their growing influence on global consumers. Companies that do everything from manufacturing phones to operating social-media platforms now account for nearly 40% of the S&P 500, on pace to eclipse a record of 37% from 1999, according to a Dow Jones Market Data analysis of annual market-value data going back 30 years. Apple accounts for more than 7% of the index on its own. Early last month, it accounted for 8% of the S&P, the largest share ever for any stock in data going back to 1998. Trends like remote work and cloud computing are driving growth at these firms, helping tech companies expand their businesses when many are struggling. Yet the concentration of gains in a narrow group of companies concerns many investors, who worry that stocks are too dependent on the sector and that a significant pullback in a few names could bring down markets.