For years, Tiffany & Co. has waged war in the courts on counterfeiters of its jewelry, watches and other luxury goods. In addition to low-level peddlers of its knock-off goods, the jeweler and its lawyers at Gibson, Dunn & Crutcher have also targeted bigger prey, such as websites like eBay Inc. that allegedly provide venues for the fakes to be bought and sold.

Last year Tiffany struck out in litigation against eBay, and now it’s suffered another setback in its fight against counterfeiters. On Monday a Manhattan federal magistrate judge denied Tiffany’s motion to compel three Chinese banks with New York branches to produce subpoenaed documents related to online sales. The judge was swayed by the banks’ lawyers at White & Case and Allen & Overy, who had argued that their clients would violate Chinese law if they complied with a U.S. court order to produce the documents.