The U.S. became a global safe haven for stocks. So why do individual companies crash so easily?

News Snapshot:

Open this photo in gallery: Pedestrians pass the New York Stock Exchange as snow falls in New York, on Feb. 13.Peter Morgan/The Associated Press Stock markets in the United States are thriving again this year, outshining indexes almost everywhere else around the world, yet there is a peculiar trend playing out for individual U.S.-listed companies: Their shares can plummet at the first sign of bad news. Sometimes it happens over something as simple as a softer outlook. In the past week, shares of travel company Expedia Group Inc. EXPE-Q dropped 18 per cent in a single day after it reported...