FedEx’s warning of a sharp drop in package deliveries is rippling across the logistics sector and raising questions about the global economy. The Wall Street Journal reports that the delivery giant’s shares fell on Sept. 16 in the biggest one-day percentage drop since FedEx went public in 1978.

The impact pressured shares of rival operators, including United Parcel Service, XPO Logistics and Yellow in the U.S. and DHL owner Deutsche Post and Royal Mail in Europe. Shares of corrugated cardboard manufacturers International Paper, Packaging Corp. of America and WestRock each fell at least 11%. 

FedEx and UPS have been raising prices to offset the decline in package volumes as well as higher labor and fuel costs. Some shippers say they are struggling with the higher shipping fees amid ebbing demand and are turning to regional parcel carriers to bring their shipping costs down.