NEW YORK (AP) - FedEx expects to ship 280 million packages between Thanksgiving and Christmas, up 13% from a year ago, thanks to consumers' growing fondness for shopping online.

FedEx moves a bulk of its cheaper, lighter weight shipments from online and catalog retailers through its SmartPost service, a partnership with the U.S. Postal Service.

The forecast comes against a background of lackluster growth in the global economy.

The Memphis, Tenn., expects Dec. 10 to be its busiest day with 19 million shipments, up 10% from 2011.

Rival UPS, based in Atlanta, hasn't yet released a holiday forecast.

The National Retail Federation expects holiday sales to increase 4.1%. That would be the smallest increase since 2009. Research firm eMarketer forecasts online holiday sales will grow 16.8%, excluding travel purchases.

Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.