Tiffany & Co.’s top executive said Nov. 20 that pursuing litigation against eBay Inc. was more effective and economical at stopping counterfeit sales of its products than targeting individual sellers on the online auction site.

At a hearing in federal court in Manhattan, Michael J. Kowalski, the jewelry retailer’s chairman and chief executive, said it has been very difficult to pursue individual sellers who list knockoffs on eBay, with little economic return. He described the counterfeit sellers as “phantasms” who have adopted new identities and returned to selling on the Web site.