
Boston-based law firm Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. has filed a lawsuit against its former client Parus Holdings, Inc., alleging the company failed to pay over $2 million in “success fees” tied to a series of lucrative patent litigation outcomes. The case, filed in the U.S. District Court for the District of Massachusetts, sheds light on the growing tension between law firms and clients over performance-based compensation structures in intellectual property cases.
Background: A Partnership Built on Patent Enforcement
According to Mintz’s complaint, the firm entered into a 2019 engagement agreement with Parus Holdings, a Texas-based technology company specializing in voice-enabled and AI-driven communication technologies. Under the agreement, Mintz agreed to provide legal services, including portfolio evaluation, patent enforcement strategy, and litigation support, with part of its compensation tied to the results achieved through enforcement actions.
Parus had long sought to protect its innovative intellectual property, which includes patents covering voice browsing, speech recognition, and voice-command technologies. These patents have been at the center of multiple lawsuits filed against major technology corporations such as Apple, Google, Samsung, and LG, alleging infringement on Parus’s proprietary voice-assistant and voice-browsing innovations.
The Dispute Over Success Fees
Mintz claims that under the terms of their engagement, the firm was entitled to receive contingent success fees based on recoveries or settlements resulting from Parus’s patent enforcement efforts. The firm alleges that after it provided years of extensive legal services—including case preparation, filings, and negotiation strategy—Parus received financial recoveries from several of its infringement lawsuits.
However, Mintz asserts that Parus has refused to pay the agreed-upon success fees, totaling more than $2 million. The firm argues that it upheld its end of the agreement by helping Parus achieve favorable results in its intellectual property disputes, entitling it to the promised compensation.
According to the complaint, Parus “wrongfully retained the benefits” of Mintz’s legal work while refusing to pay for the contingent portion of the agreement. Mintz is now seeking damages, interest, and attorney’s fees for breach of contract and unjust enrichment.
Details from the Engagement Agreement
The 2019 engagement agreement reportedly outlined specific performance benchmarks that would trigger success fees once certain litigation milestones or settlements were achieved. Such arrangements are common in high-stakes patent litigation, where clients may be unable or unwilling to pay full hourly fees up front and instead offer a percentage of any recovery.
Mintz contends that it provided significant value by developing Parus’s IP litigation framework, identifying infringement targets, and initiating enforcement actions that led to successful outcomes. The firm’s filing argues that Parus’s refusal to pay violates both the spirit and the letter of the contract.
Parus, for its part, has not yet filed a formal response, but sources familiar with the dispute suggest the company disputes the characterization of the recoveries as triggering events under the fee agreement.
Parus Holdings’ Legal History
Parus Holdings has been a prominent player in the voice-assistant patent enforcement space for over a decade. The company, originally founded in Chicago and now headquartered in Austin, Texas, has amassed a robust patent portfolio in voice-interaction technologies.
In 2021 and 2022, Parus launched several high-profile patent infringement lawsuits against major tech companies, including Google and Samsung, asserting its rights over technology enabling users to perform tasks via voice commands. Many of these cases were litigated or strategically settled, forming the backdrop for Mintz’s current fee claim.
Parus’s aggressive enforcement strategy has also drawn industry scrutiny, with critics accusing it of pursuing “patent monetization” rather than product innovation. However, Parus has maintained that it merely seeks to protect its legitimate intellectual property and ensure fair compensation for the use of its technologies.
A Broader Issue in the Legal Industry
The Mintz-Parus dispute underscores a broader trend in the legal profession—especially in intellectual property law—toward performance-based or contingent fee arrangements. Such agreements can benefit clients by reducing upfront legal costs, but they also increase the risk of post-litigation fee disputes if the parties disagree on what constitutes a “success.”
For law firms like Mintz, success-based compensation provides the potential for significant rewards in exchange for the risk of partial or delayed payment. However, when clients fail to honor these agreements, firms can face lengthy legal battles to recover fees.
Legal industry experts note that success-fee disputes have become increasingly common as firms seek creative billing arrangements amid competitive pressures and rising litigation costs. The outcome of this case could have implications for how law firms structure similar agreements in the future, especially in the patent enforcement arena.
What Comes Next
Mintz is seeking $2.1 million in unpaid fees, plus interest and costs, and is asking the court to enforce the agreement’s terms. The case will test how strictly courts interpret contingent fee arrangements when specific definitions of “success” are contested.
For now, the dispute remains before the Massachusetts federal court. Neither Mintz nor Parus has issued public comments beyond the filings.
As the legal battle unfolds, the case serves as a reminder to law firms and clients alike about the importance of clear, unambiguous engagement terms—especially in high-stakes IP litigation where financial recoveries can be substantial.
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