Warehouse superstore Costco is in big trouble for selling imitation jewelry.

A federal judge says the company needs to pay Tiffany & Co. $5.5 million for selling fake Tiffany diamond engagement rings.

The judge says Costco's jewelry buyers requested vendors to copy the Tiffany designs and sell the rings branding them as "Tiffany" when they weren't.

According to fortune.com, Tiffany is also entitled to punitive damages, a New York jury ruled.

Last week, Costco said it would not comment because deliberations were continuing. Tiffany also declined to comment on the case.

Fortune says the $5.5 million "represents the amount of profit Costco made from the sale of the rings that would fairly compensate Tiffany."