NEW YORK - Call it the pregame show for Santa and his elves.

Monday was expected to be the busiest day in FedEx history, with nearly 16 million packages moving on its conveyer belts, trucks and planes. That would be up 13 percent from 14.2 million on the busiest day last year, and double what the company handles on a normal day.

That jump in shipments bodes well for the nation's retailers, online stores and larger rival UPS, which has its single busiest day next week.

Industry analysts and economists track FedEx and UPS shipping performance for signs of consumer spending trends and the health of the broader economy because both shippers handle a wide variety of goods shipped between manufacturers and consumers.

About half of the FedEx increase this year is from the company's SmartPost partnership with the U.S. Postal Service. SmartPost moves lighter, cheaper packages through FedEx that are then delivered by a postal worker. Growth of online and catalog purchases is driving the gain in that unit and across the company.

Nationwide, online holiday spending since Nov. 1 is up 12 percent over last year to nearly $22 billion, according to research company comScore. Dec. 6 and Dec. 8 ranked in the top five days for online spending ever, comScore said. Online orders are likely to spike again this Friday, which many merchants are promoting as "Free Shipping Day."

Online spending increases come with modestly brighter prospects for holiday spending in general. Retail experts predict overall spending will increase by 2 percent to 4 percent over last year.

Severe weather, including a weekend blizzard in the Midwest, did not hinder deliveries significantly on FedEx's busiest day, spokeswoman Deborah Willig said Monday.

UPS expects its busiest day closer to Christmas - on Dec. 22, when it will move about 24 million packages. That's 60 percent more than a normal day. The Atlanta company will accept packages for Christmas delivery through Dec. 23.

FedEx's busiest day is the high-water mark of a holiday season in which it expects to move 223.3 million shipments worldwide. That's 86 packages delivered every second from Thanksgiving Day to Christmas Eve. UPS will deliver almost double that between the two holidays.