IP Law Daily, TRADEMARK NEWS: Comet ML sues Perplexity AI over planned use of ‘COMET’ mark for AI browser, (May 13, 2025)

By Saurabh Kashyap, B.A., LL.B., LL.M.

Comet alleges Perplexity’s new browser infringes its registered mark, risks market confusion, and threatens its goodwill.

Comet ML Inc. has filed a trademark infringement and unfair competition suit in the Northern District of California against Perplexity AI, Inc., seeking an injunction and damages over Perplexity’s announced plan to launch a new AI-powered browser called “COMET.” Comet claims that the product’s name unlawfully appropriates its federally registered COMET® mark and is likely to mislead customers into believing that Perplexity’s browser is affiliated with or endorsed by Comet. The complaint accuses Perplexity of willfully adopting the mark despite Comet’s prior use, and of continuing its marketing efforts even after Comet issued a cease-and-desist letter and obtained an interim injunction in Germany (Comet ML Inc. v. Perplexity AI, Inc., No. 3:25-cv-04088 (N.D. Cal. filed May. 12, 2025)).

Background. The plaintiff, Comet ML Inc., is a Delaware corporation having a place of business in New York that offers a platform for managing artificial intelligence and machine learning workflows. Its COMET®-branded software supports experiment tracking, model comparison, hyperparameter optimization, dataset management, and integration with major ML frameworks. The defendant, Perplexity AI, Inc., is a Delaware-incorporated, San Francisco-based AI startup founded in 2022 by engineers from OpenAI and Meta. It is backed by prominent investors such as Jeff Bezos and Nvidia.

Comet ML has used the COMET® mark in commerce since at least July 7, 2017, in connection with its AI and ML lifecycle management platform. The platform allows users to train and monitor models, store and visualize results, and collaborate across teams. In 2018, Comet ML applied for federal registration of COMET® and COMET.ML® under Class 42 for software-as-a-service tools supporting AI development. The USPTO issued U.S. Registration Nos. 5,682,167 and 5,682,168 in 2019. Both marks are now incontestable under Section 15 of the Lanham Act.

According to Comet’s complaint, the COMET® brand has acquired strong goodwill and market recognition among enterprise AI users. The company asserts that its continuous and exclusive use of the mark for over seven years has resulted in widespread consumer association of the COMET® name with its platform and services.

Perplexity’s adoption of “COMET.” On February 24, 2025, Perplexity publicly announced the upcoming launch of a new AI browser product called "COMET," described as a "browser for agentic search" that would use large language models to locate, understand, and synthesize information with minimal user input. Agentic search refers to the emerging class of AI tools that autonomously perform tasks based on natural language instructions. Perplexity launched a waitlist page promoting the product under the disputed mark in conjunction with the announcement.

Comet alleges that Perplexity’s COMET browser performs similar functions to its own COMET®-branded platform and targets the same market segment—technical users of AI systems, including startups, enterprises, and academic institutions. Both products, Comet asserts, rely on machine learning workflows, integrate with LLMs, and aim to optimize the user’s interaction with AI systems to increase productivity and accuracy.

Prior knowledge and disregard. Comet contends that Perplexity adopted the COMET mark with full knowledge of its existing rights. The complaint alleges that the similarity between the parties’ product offerings, branding, and target markets makes it implausible that Perplexity was unaware of Comet ML’s preexisting mark. Comet further asserts that the “ML” in its name (standing for machine learning) should have made its area of operation obvious to Perplexity.

Despite receiving a cease-and-desist letter from Comet's counsel on February 25, 2025, Perplexity allegedly continued promoting the COMET-branded browser without change. Comet also claims that Perplexity has refused to take corrective steps and is expanding its use of the mark in disregarding trademark norms and judicial authority.

Foreign proceedings. In April 2025, Comet obtained a preliminary injunction from the District Court of Düsseldorf in Germany, prohibiting Perplexity from using the COMET mark in connection with agent-based AI software and browsers in the German market. The German court enjoined the use of “comet” in the course of trade related to agentic AI systems and machine learning. Nevertheless, Comet asserts that Perplexity continues to market the product in the U.S. under the same branding.

Trademark infringement claim. In its first claim for relief, Comet alleges that Perplexity's use of the COMET mark infringes its registered trademarks under Section 32(1) of the Lanham Act, 15 U.S.C. § 1114(1). Comet argues that the unauthorized use of an identical mark for similar AI software will likely cause consumer confusion regarding source, sponsorship, affiliation, or endorsement. The complaint emphasizes that Perplexity's actions are deliberate, knowing, and intended to capitalize on Comet's reputation.

Comet seeks damages, disgorgement of Perplexity’s profits, and injunctive relief barring the use of the COMET mark in connection with any AI browser or related services that overlap with Comet ML’s offerings.

False designation and unfair competition. In its second claim, Comet invokes Section 43(a) of the Lanham Act, 15 U.S.C. § 1125(a), alleging that Perplexity’s use of the COMET mark constitutes false designation of origin. Comet asserts that the mark falsely suggests a connection or affiliation between the two companies, leading consumers to mistakenly believe that Perplexity’s product originates from, or is endorsed by, Comet ML.

Perplexity’s refusal to rebrand, even after notice of Comet’s prior rights, is cited as evidence of bad faith. The complaint notes that Comet’s goodwill in the COMET® mark is at risk of dilution, erosion, and association with a competing product it does not control.

California statutory and common law claims. Comet also asserts claims under California’s Unfair Competition Law, Cal. Bus. & Prof. Code § 17200 et seq., and California common law. These causes of action mirror the federal claims but are grounded in state consumer protection and trademark principles. Comet alleges that Perplexity’s acts are unlawful, unfair, and fraudulent, and have caused and will continue to cause harm to its business and reputation.

The complaint highlights that this is not the first time Perplexity has been accused of misappropriating others’ intellectual property. Comet references a copyright lawsuit filed by Dow Jones & Co. and the New York Post against Perplexity in December 2024, and another trademark suit filed in January 2025 by a company called Perplexity Solved Solutions Inc.

Relief. Comet requests a permanent injunction barring Perplexity and its affiliates from using the COMET mark or any confusingly similar variation in connection with AI software, browsers, or related products. It seeks actual damages, statutory damages of up to $2 million per mark under 15 U.S.C. § 1117(c), and punitive damages under California law. Comet also seeks attorneys’ fees, costs, and pre-judgment interest.

Additionally, the complaint requests that Perplexity cease any acts likely to mislead the public about an affiliation between the two companies and withdraw all marketing and domain uses of the disputed mark.

The Case is No. 3:25-cv-04088.

Attorneys: Eleanor M. Lackman (Mitchell Silberberg & Knupp LLP) for Comet ML Inc.

Companies: Comet ML Inc.; Perplexity AI, Inc.

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