Amrith Ramkumar

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.