New orders at factories jumped by an unexpectedly large 1 percent in December despite a drop in transportation equipment orders, while inventories shrank, a government report showed on Thursday.

Analysts polled by Reuters expected orders to increase by 0.5 percent. Factory orders for November were revised up to a 1 percent gain.

Transportation orders fell by 0.5 percent on a 34.1 percent drop in civilian aircraft orders. Excluding transportation, new orders rose 1.2 percent in the month.

Inventories fell for the first time in three months, dipping 0.1 percent.

The inventories-to-shipments ratio slipped to 1.29, the lowest since August 2008.

(Reporting by Mark Felsenthal, Editing by Neil Stempleman)