Wall Street spent last Thursday reminding investors how quickly a favorite theme can turn. Worries that Democratic midterm wins could bring tighter rules for artificial intelligence and data centers sent technology stocks sharply lower. The damage spread well beyond the group that was under the microscope.
The Nasdaq Composite fell 5.52%, its biggest one-day drop in 19 months, and closed more than 10% below its October record, a slide that put it in a correction. The S&P 500 lost 4.36%, its...