When you think of where to buy your engagement ring, you might think of Zales, Tiffany & Co., or Blue Nile. But if you've ever walked past the diamond counters at a Costco warehouse, you might be ...

NEW YORK (AP) — A Tiffany & Co. subsidiary is suing Costco, claiming the wholesale club operator has been selling engagement rings wrongly labeled “Tiffany” rings. The high-end jeweler filed lawsuit ...

Costco's going to pay for selling "Tiffany" engagement rings that weren't made by Tiffany. U.S. District Judge Laura Taylor Swain ruled on Monday that Tiffany is entitled to $11.1 million in trebled ...

Tiffany has beaten Costco to the tune of at least $19.4 million in the trademark infringement battle over alleged knock-off rings that pitted the luxury jeweler against the membership warehouse giant.