Costco sold counterfeit Tiffany engagement rings, rules US judge

New York

COSTCO Wholesale Corp wilfully infringed Tiffany & Co's trademarks by selling counterfeit diamond engagement rings bearing the luxury retailer's name and must face a jury trial to assess damages, a US judge ruled on Tuesday.

US District Judge Laura Taylor Swain in Manhattan rejected claims by Costco that Tiffany's trademarks were invalid because they sought to prevent others from using the word "Tiffany" as a generic description of a type of ring setting.

Instead, Judge Swain said evidence established that Costco, the largest US warehouse club chain, had infringed Tiffany's trademarks by selling engagement rings and confused consumers by using the w…