The US stock market is more concentrated than it’s been in decades, with a small number of stocks accounting for an unusually large share of market capitalization. While it’s making some investors uneasy, Ben Snider, a senior strategist on the US portfolio strategy team in Goldman Sachs Research, and Peter Callahan, who covers the US technology, media, and telecommunications markets business in Global Banking & Markets, point out on Goldman Sachs Exchanges that these stocks' valuations reflect strong earnings.If you'd like to learn more, visit GS.com and sign up for Briefings, a weekly newsletter from Goldman Sachs about trends spanning markets, industries, and the global economy.