The Commerce Department announced the sales at U.S. retailers fell 1.2 percent m-o-m in December, following a revised 0.1 percent m-o-m advance in November (originally a gain of 0.2 percent m-o-m). That was the biggest monthly drop since September 2009.

Economists had expected total sales would increase 0.2 percent m-o-m in December. 

The December decline came despite a notable surge in sales by motor vehicles and parts dealers (+1.0 percent m-o-m).

Excluding auto, retail sales also dropped 1.8 percent m-o-m after a revised flat m-o-m performance in the previous month (originally a gain of 0.2 percent m-o-m), missing economists’ forecast for a 0.1 percent m-o-m advance. 

Meanwhile, closely watched core retail sales, which exclude automobiles, gasoline, building materials and food services, and are used in GDP calculations, fell 1.7 percent m-o-m in December, following a revised 1.0 percent m-o-m advance in October (originally a 0.9 percent m-o-m increase). 

In y-o-y terms, the U.S. retail sales rose 2.3 percent in December, decelerating growth pace from November’s revised increase of 4.1 percent (originally a 4.2 percent gain).