The tumbling stocks reflect Wall Street’s concerns that the businesses of Uber, Lyft and Doordash would suffer under a regulatory shift. Classifying drivers as contractors allows tech companies to contain their labor costs because they are not usually subject to minimum-wage laws, vacation time, unemployment insurance and other benefits. But this model has left drivers in a more vulnerable position, as highlighted last year when many found themselves without rides as coronavirus cases soared and travel ground to a halt. The government had to create a new unemployment insurance program for gig workers during the pandemic, which the companies don’t pay into.