FedEx (FDX) shares are down down about 2% to $162.29 after The Wall Street Journal said Amazon (AMZN) is preventing its third-party sellers from using the shipper’s ground delivery network for its Prime shipping. In his report on the new development, The Wall Street Journal’s Paul Ziobro noted that the e-commerce giant has previously stopped using FedEx for its own deliveries in the U.S., but third-party sellers had still been able to use the company’s service for their deliveries.