Major U.S. stock indexes finished higher Thursday after a late burst of buying led by technology and financial companies reversed an early slide.

News of a spike in the number of confirmed cases and fatalities from a virus outbreak in China put investors in a selling mood for most of the day, overshadowing a batch of mostly solid company earnings reports.

Traders have been worried that the outbreak could end up dampening global economic growth. But those concerns appeared to ease by late afternoon, after the director general of the World Health Organization said that the organization was not r...