Giant US retail group Costco is cutting exposure to container ships as rates slump and capacity supply improves.

The company claimed last year to have chartered three small vessels for three years, and some box capacity, as congestion rose and freight costs rocketed.

Chief Financial Officer Richard Galanti told analysts on a conference call that Costco later added four more ships, as well as more containers, to save money.

But he also said the group will take a $93 million (€87 million) charge in its first quarter “mostly related to downsizing our charter shipping activities."