Mammoth Hockey 10th Circuit Injunction: Appeal Heard

• The 10th Circuit is reviewing a trademark dispute between bagmaker Mammoth Hockey and the Utah Mammoth hockey team.
• Mammoth Hockey appealed a district court's denial of its motion for a preliminary injunction against the team.
• The central legal argument involves 'reverse confusion,' where a larger junior user allegedly overshadows a smaller senior user.
• Attorneys debated whether the Utah Mammoth acted in bad faith when selecting its name, a factor the district court did not address.
• The court has not yet indicated when it will rule on the Mammoth Hockey 10th Circuit injunction request.

This ongoing 10th Circuit trademark dispute underscores the critical importance of diligent trademark clearance searches and the potential for 'reverse confusion' claims, particularly when a new, high-profile entity adopts a mark already in use by a smaller, senior business.

A significant trademark dispute involving the Utah Mammoth professional hockey team and Portland, Oregon-based bag manufacturer Mammoth Hockey recently reached the 10th Circuit Court of Appeals. The controversy began in 2025 when Mammoth Hockey, asserting its status as a senior mark-holder, requested the Utah team to cease selling merchandise, particularly bags, that were causing customer confusion. In response, the Utah Mammoth initiated legal action against the bagmaker.

The heart of the current legal battle is Mammoth Hockey's appeal of a December 23, 2025, decision by U.S. District Judge David Barlow, who denied their motion for a preliminary injunction. The bagmaker sought to block the hockey team from continuing to use the 'Mammoth' name and sell related products. The appellate hearing took place in Denver at the Byron White U.S. Courthouse, just four days before the Utah Mammoth were scheduled to commence their 2026 season against the Colorado Avalanche at Ball Arena. Notably, the Utah Mammoth had previously defeated the St. Louis Blues 5-3 in a preseason game on September 22, 2024, in Des Moines, Iowa.

This 10th Circuit trademark dispute centers on complex questions of trademark rights and market presence. Mammoth Hockey specializes in high-end sports bags, with products often exceeding $300. However, the Utah Mammoth has also entered the merchandise market, offering bags priced between $83 and $199, alongside jerseys, hats, pickleball paddles, and even Yeti brand coolers, creating a direct overlap in product categories.

During the appellate proceedings, attorneys for both sides presented their core arguments. Gerald Griffin, representing Mammoth Hockey, contended that his client's case hinges entirely on the principle of 'reverse confusion trademark.' This legal concept describes a scenario where a more powerful and affluent junior user enters the market, potentially overwhelming and effectively drowning out the smaller, established senior competitor. Griffin asserted that the Utah Mammoth adopted its name with a clear disregard for Mammoth Hockey's existing use of the mark.

Griffin further highlighted that the district court, presided over by Judge Barlow, failed to address whether the Utah Mammoth acted in bad faith when selecting its mark. He emphasized that the law mandates a reasonable level of research in trademark selection, and evidence would demonstrate the hockey team's awareness of Mammoth Hockey's prior existence. According to Griffin, the Utah team had a duty to contact Mammoth Hockey during its name investigation process.

Conversely, Bruce Ewing, representing Uyte LLC, the parent company of the Utah Mammoth, defended the team's choice of name. He argued that numerous third parties, including other sports teams, hockey teams, and bag manufacturers, already utilize the term 'mammoth.' This widespread usage, Ewing suggested, led his client to reasonably conclude they could also adopt the name. The team had initially considered 'Yeti' but opted for 'Mammoth' after determining that the popular cooler brand would likely challenge the 'Yeti' mark.

The appellate panel, comprising U.S. Circuit Judges Scott Matheson and Gregory Phillips, both appointed by Barack Obama, along with U.S. District Judge David Urias, visiting from New Mexico and appointed by Joe Biden, closely examined the arguments. Judge Matheson specifically questioned whether the available evidence sufficiently supported a preliminary injunction at this stage of the proceedings, asking if such a request might be considered 'immature.'

In response to Judge Matheson's inquiry, Gerald Griffin for Mammoth Hockey stressed the urgency of the situation. He argued that if the Utah Mammoth is permitted to continue saturating the market with its brand, the damage to Mammoth Hockey's senior mark would become irreparable. This exchange underscores the high bar for obtaining a trademark preliminary injunction, which requires demonstrating a likelihood of success on the merits and irreparable harm.

The 10th Circuit did not provide any indication regarding when or how it would render its decision in the Mammoth Hockey 10th Circuit injunction appeal, nor did the judges comment on whether they would be watching the upcoming Sunday game.

This ongoing 10th Circuit trademark dispute underscores the critical importance of diligent trademark clearance searches and the potential for 'reverse confusion' claims, particularly when a new, high-profile entity adopts a mark already in use by a smaller, senior business. The case serves as a stark reminder for legal counsel to conduct exhaustive investigations into existing marks to prevent costly and protracted litigation.

The outcome of Mammoth Hockey v Utah Mammoth will provide further clarity on the standards for granting preliminary injunctions in trademark cases within the 10th Circuit, especially concerning the consideration of alleged bad faith in mark selection. The appellate court's eventual ruling could significantly influence how junior users, particularly those with substantial market power, approach brand development and their responsibilities to senior mark holders, reinforcing the need for proactive legal diligence.

This case serves as a reminder for trademark attorneys to conduct exhaustive clearance searches and advise clients on the potential for 'reverse confusion' claims, especially when a larger entity adopts a mark similar to a smaller, senior user. The 10th Circuit's eventual ruling will provide further guidance on the standard for preliminary injunctions and the consideration of bad faith in trademark selection.

Source: Original reporting via Courthouse News