The clobbering tech shares have taken in recent days has magnified not only how influential these companies have become in people’s everyday lives, but how much sway they’ve gained in global stock markets.
The NYSE FANG+ Index—which tracks 10 global tech heavyweights, including Facebook Inc., Apple Inc. and China’s Alibaba Group Holding—slumped 5.6% on Tuesday, its worst one-day drop since its inception four years ago.
Investors’...