Proving Copying at a Cost: (Another) Cautionary Tale for Brands in Dupe Litigation

Dupe lawsuits do more than challenge copycats – they put a brand’s IP on trial. The recent jury verdict in Deckers Outdoor Corp. v. Last Brand, Inc. serves as a reminder that enforcing against alleged “dupe” products can expose weaknesses in a brand’s asserted rights. If a brand’s IP rights have not been objectively vetted before the first cease and desist letter is sent, the fallout may extend far beyond a single lawsuit.

Last Brand Inc., doing business as Quince, is a direct-to-consumer retailer specializing in lower-cost versions of premium products and is widely known for its dupe offerings. In 2023, Deckers Outdoor Corp., owner of the UGG brand, sued Quince over its Australian Shearling Mini Boot, which Deckers claimed copied the look and feel of UGG designs. In its second amended complaint, Deckers alleged federal and state trade dress infringement of three core UGG styles – the Classic Ultra Mini boot, the Bailey Button boot and the Tasman slipper – along with a design patent claim covering the ornamental design of the Classic Ultra Mini boot.

The case narrowed sharply before trial. In an Oct. 2, 2025 decision, the court granted summary judgment in part for Quince on Deckers’ trade dress claims for the Classic Ultra Mini boot and Tasman slipper. The court pointed to two core issues: functionality and a crowded field. Evidence that design features such as seams, shape and construction affected cost or usability raised functionality concerns, while a saturated market of similar shearling boots and slippers undermined any claim that the designs uniquely signaled UGG as the source. Deckers later dropped its remaining trade dress claim for the Bailey Button boot, leaving the design patent as its sole path to relief at trial.

On June 15, Deckers won the infringement battle but lost the patent war: The jury found Quince’s boot infringed UGG’s design patent but that the patent itself was invalid. Quince’s invalidity case leaned into the same themes previewed at summary judgment: The patent captured features already ubiquitous in the shearling boot market and relied on elements driven by function or standard construction. Under this framing, the design no longer read as a standout innovation but rather as a familiar silhouette drawn from a crowded style playbook. Thus, despite the jury’s finding of infringement, since invalidity is a complete defense, Deckers was left without recovery – and without a patent.

This decision highlights several practical lessons for brands navigating the dupe economy: 

• Make sure your IP can withstand challenge. A finding of infringement cannot carry the case if the asserted IP does not hold up. 
• Do your homework up front. In crowded markets, similar designs can undermine claims of distinctiveness and support patent invalidity defenses.
• Bring the right case. Weigh the risks before bringing a case – an unsuccessful claim can amplify, rather than deter, the dupe market.

The lesson from Deckers is straightforward: Before putting a dupe on trial, make sure your own IP is ready for the spotlight. Successful enforcement needs more than evidence of copying – it requires rights that can withstand validity challenges, a record supporting distinctiveness, and a thoughtful, consistent strategy. Otherwise, a lawsuit intended to deter copycats may end up strengthening them.

The case is Deckers Outdoor Corp. v. Last Brand, Inc., No. 4:23-cv-04850 (N.D. Cal. June 15, 2026). It was assigned to Judge Araceli Martínez-Olguín.