Amazon Delivery Model Threatened by Drivers’ Early Labor Law Win

Amazon.com Inc.’s sprawling delivery network is at risk of being reordered after a federal labor board official determined that the e-commerce giant jointly employed the drivers of one of its contractors.

The preliminary decision by a National Labor Relations Board regional director on Thursday could make it harder for US businesses to distance themselves from labor-law liability by outsourcing front-line work to contractors, if it withstands a lengthy legal process.

Still, it opens the door for the International Brotherhood of Teamsters and other unions to organize Amazon drivers nationwide—and force the company to come to the bargaining table—two things the ...