Updated from 3.55 p.m. ET to include closing prices and reference to UPS SurePost product.MEMPHIS TheStreet) -- Christmas season is approaching, so it's time for FDX ( FDX) and UPS ( UPS), which print money throughout the year, to print even more money. FedEx said Monday that Dec. 12, which is just 49 days away, will be the busiest day in its history. On that day, the overnight package carrier expects to move 17 million shipments, almost double its daily volume. Much of the increase will be driven by FedEx SmartPost, a residential shipping service which delivers retailers' shipments to the post office for final delivery to individual homes. FedEx said it will hire about 20,000 seasonal workers.