Import cargo volume at major US retail container ports is set to remain unchanged year-on-year in December, as stores bring in the last round of merchandise for the holiday season.

According to the Global Port Tracker report released by the National Retail Federation (NRF) and Hackett Associates, import volume was expected to total 1.37m containers. This would be down on the 1.51m predicted for last month

"The holiday season is well under way and merchants are doing the final balancing act of matching supply to demand," said NRF vice president for supply chain and customs policy Jonathan Gold. "Retailers went into the season with strong inventories that ensured consumers would have a good depth and breadth of selection, and that should hold true for the remainder of the season." 

Cargo import numbers do not correlate directly with sales because they count only the number of cargo containers, not the value of the merchandise inside them. Nonetheless, the amount of merchandise imported provides a rough barometer of retailers' expectations. 

Ports covered by Global Port Tracker handled 1.56m Twenty-Foot Equivalent Units (TEU) in October, the latest month for which after-the-fact numbers are available. That was down 4.1% from September, and down 0.1% from a year ago. One TEU is one 20-foot-long cargo container or its equivalent. 

November was estimated at 1.5m TEU, up 7.4% from 2014, and December is forecast at 1.44m TEU, down 0.1% from last year. Those numbers would bring 2015 to a total of 18.3m TEU, up 5.5% from last year. The first half of 2015 totalled 8.9m TEU, up 6.5% over the same period last year.

January 2016 is forecast at 1.46m TEU, up 17.9% from weak numbers seen a year earlier just before West Coast dockworkers agreed on a new contract that ended a months-long labour dispute. February 2016 is forecast at 1.4m TEU, up 16.9%, also skewed by the labour dispute. 

March is forecast at 1.35m TEU, down 22.4% from a year ago because of large volumes seen after the contract agreement. Patterns are expected to return to normal in April, which is forecast at 1.51m TEU, down 0.3% from last year.

Hackett Associates founder Ben Hackett believes retailers are still working off excess inventory built up after the West Coast port situation and sustained by warm weather that has diminished the demand for winter clothing.