Core Viewpoint - Lululemon has filed a lawsuit against Costco, accusing the retailer of selling knockoff versions of its popular products, highlighting the challenges faced by established brands in combating "dupe culture" [1][2]. Group 1: Lawsuit Details - The lawsuit, filed in California, claims that Costco is selling and manufacturing knockoffs of Lululemon's Scuba sweatshirts, Define jackets, and ABC pants, alleging trade dress infringement and unfair competition [2]. - Lululemon seeks compensation for lost profits and significant harm to its brand and reputation due to Costco's actions [2]. Group 2: Legal Challenges - Winning a trademark infringement lawsuit over dupe products is difficult, as the original manufacturer must prove that the copycat product could confuse customers into believing it is the real item [3][4]. - The burden of proof lies with the original company to demonstrate that the copycat product has caused confusion and impacted their business, which is challenging to establish [4]. Group 3: Industry Context - The rise of "dupe culture" has been significantly influenced by social media platforms like TikTok, where consumers actively seek and share cheaper alternatives to high-end products [6]. - TikTok videos featuring the dupe hashtag have garnered over 6 billion views, indicating a growing acceptance of purchasing knockoff products among younger consumers [6]. Group 4: Related Legal Cases - A notable case involved e.l.f. Cosmetics, which admitted to creating a product that mimicked Benefit Cosmetics' mascara but was ruled not to infringe on trademarks due to insufficient evidence of customer confusion [7][8]. - Other companies, such as Mondelez International and Williams-Sonoma, are also pursuing legal action against retailers and websites for similar trademark infringement claims [8].

Core Viewpoint - Lululemon Athletica has filed a lawsuit against Costco Wholesale, alleging trademark infringement due to the sale of clothing that closely resembles Lululemon's designs [2][3]. Group 1: Lawsuit Details - The lawsuit was filed in a California federal court, where Lululemon claims that Costco has unlawfully capitalized on its reputation and goodwill by selling unauthorized apparel that infringes on Lululemon's trade dress and design patents [3]. - Lululemon identified six specific products sold by Costco that allegedly violate its trademarked designs, including a Kirkland Signature pair of pants and jackets from various brands [5]. - The company is seeking damages for potential lost sales due to Costco's sale of these similar products and has requested a jury trial [5]. Group 2: Market Reaction - Despite the lawsuit, neither Lululemon nor Costco's stock prices have been significantly affected, with both companies seeing slight increases in premarket trading [6]. Group 3: Consumer Behavior - The lawsuit highlights a trend where consumers actively seek out "dupes" of popular products, with Lululemon referencing articles from The Washington Post and Wirecutter that discuss Costco's products as near-identical replicas of its own [4].