FedEx Corp.  expects its busiest day in company history to be Dec. 13 as consumer activity peaks in a holiday shipping season the shipper projects to be about 11 percent bigger than last year.

Shares rose on the news but were still down 14 cents at $88.34 in recent trading on broader market declines.

The growth comes as shippers have seen solid rebounds from the weakness of the last several years. FedEx reported in September its quarterly profit more than doubled on higher volume as it boosted its earnings outlook for the year twice in 2010.

The company said Thursday it expects to move nearly 16 million shipments around the world Dec. 13 — up more than 11 percent from last year’s busiest day, when the company handled 14.2 million shipments. FedEx said that on average, it moves more than 8 million packages daily.

For the holiday season, it also expects an 11 percent jump in shipments in 2010 from  2009, with more than 223.3 million shipments moving between Thanksgiving and Christmas.

The company said it expects items such as books from big Internet retailers as well as retail inventory such as apparel, consumer electronics and luxury goods to drive volumes. It also highlighted FedEx’s SmartPost service — mainly used by online retailers and catalogers that ship high volumes of lighter shipments to residential customers.

Holiday sales — and in turn, shipments — are expected to be better this year as consumers are seen more willing to open their wallets to discretionary spending as the economy has improved from last year’s levels.