In the United States, Apple, Google's parent company and other tech companies account for nearly 24 percent of the Standard & Poor's 500 index. But it's also a concern for skeptics who see tech stocks as overly pricey and primed for a pullback. The worries came into starker relief in recent weeks, after tech stocks tumbled more than the rest of the market. "It's a sign of the times," said Patricia Ribeiro, senior portfolio manager at the American Century Emerging Markets fund and the American Century Emerging Markets Small Cap fund. In the United States, tech stocks in the S&P 500 doubled the gain of the index through the year's first 11 months.

Source: ABC News December 07, 2017 19:18 UTC