The US Supreme Court has declined to hear an appeal by footwear specialist Deckers Outdoor on whether its Ugg boots should have been subject to a lower import duty.

According to court documents, when Deckers imported the Ugg Classic Cro­chet boots, which have a knitted upper area and a rubber sole, with no laces, buckles, or other fasteners, Customs classified them as footwear of the 'slip on' type. Under HTSUS subheading 6404.19.35, this type of footwear carries a 37.5% duty.

But Deckers argued the boots should have been classified under subhead­ing 6404.19.90, which covers "footwear with outer soles of rubber...and uppers of textile materials", and would have been subject to a much lower duty rate of 9%.

Customs denied the protest, and Deckers filed suit in the Court of International Trade (CIT). The group argued that subheading 6404.19.35 includes shoes, but not boots. The US Court of Appeals for the Federal Circuit affirmed the CIT's judgement.

As well as rejecting Deckers' petition, the Supreme Court also denied a motion by the American Association of Exporters and Importers to file an amicus brief.

Deckers has not yet responded to requests for comment.