Case Law
Mammoth Hockey 10th Circuit Injunction: Appeal Heard
In 2025, the Portland, Oregon-based company Mammoth Hockey appealed to the 10th Circuit Court of Appeals in Denver, Colorado, seeking to block the Utah Mammoth hockey team from selling bags under the same name, following a district court's denial of a preliminary injunction.
This legal dispute arose after Mammoth Hockey, claiming ownership of a senior mark, sent a cease-and-desist letter to the Utah Mammoth hockey team in June 2025. The hockey team, which had announced its name in May 2025 after abandoning an initial choice of "Yeti" due to potential trademark conflicts, began marketing bags alongside other merchandise. In response, the Utah Mammoth, represented by its parent company Uyte LLC and attorney Bruce Ewing, sued Mammoth Hockey to protect its new name, arguing that the term "mammoth" is widely used by various third parties, including other sports teams and bagmakers. On December 23, 2025, U.S. District Judge David Barlow denied Mammoth Hockey’s motion for a preliminary injunction, prompting the current appeal to the 10th Circuit.
This case carries significant implications for trademark law, particularly concerning the likelihood of confusion between marks used on related goods and the scope of protection afforded to senior mark holders. It highlights the challenges businesses face when adopting names that, while seemingly generic or widely used, may overlap with existing trademarks, especially when expanding into new product categories. The outcome of this appeal will provide crucial guidance on how courts balance the rights of established brand owners against new market entrants, particularly regarding brand extensions into merchandise that might directly compete with an existing mark. For businesses, it underscores the critical importance of thorough trademark clearance and the potential for protracted and costly litigation even when a name is perceived as common.
The legal context for this dispute is primarily federal trademark law, specifically the Lanham Act (15 U.S.C. § 1051 et seq.), which governs trademark infringement and unfair competition. Key legal principles at play include the standard for demonstrating a "likelihood of confusion" between marks, the concept of a "senior mark," and the stringent requirements for obtaining a preliminary injunction. A party seeking a preliminary injunction must typically demonstrate a strong likelihood of success on the merits, irreparable harm without the injunction, that the balance of equities favors the movant, and that the injunction is in the public interest. The 10th Circuit Court of Appeals is tasked with reviewing the district court's application of these standards. The case also touches upon the doctrine of "natural expansion" of a brand, as the hockey team's foray into selling bags directly competes with the bagmaker.
Attorneys advising clients on intellectual property and branding strategies should closely monitor the 10th Circuit's decision in this matter. This case serves as a potent reminder of the necessity for comprehensive trademark searches and clearance processes, even for terms that appear to be generic or widely adopted. Businesses, particularly those in sports, entertainment, or other industries that frequently license or sell merchandise, must be acutely aware that expanding into new product lines can trigger trademark disputes with entities in seemingly unrelated sectors if there is a likelihood of confusion or if the new product falls within the natural zone of expansion of an existing mark. Clients should be proactively advised on robust trademark registration strategies and careful consideration of brand extensions to mitigate such litigation risks.
