Nvidia and Microsoft have been accused of patent theft and violating federal antitrust laws in a lawsuit filed by Xockets in a Texas court on Thursday.

According to the filing, the startup alleges Nvidia and Microsoft infringed its Data Processing Units (DPUs) patents and formed an “illegal cartel” to “avoid paying the fair market price for Xockets' patented DPU technology.”

Founded in 2012, Xockets developed its DPUs to accelerate data-intensive workloads. The company alleges its patents were originally infringed upon by networking company Mellanox after Xockets publicly demonstrated its DPU offering at a conference in 2015.

The infringement allegation was then inherited by Nvidia when it acquired Mellanox in 2020 for $6.9 billion. Xockets claims that three of the chipmaker’s DPUs – BlueField, ConnectX, and NVLink Switch – are based on patented technology.

Microsoft has also been accused of patent infringement in the lawsuit as it is alleged that as an Nvidia customer, the tech giant has “privileged access to Nvidia’s infringing GPU-enabled server computer systems and components for AI.”

In a statement after the lawsuit had been filed, Xockets said: “Nvidia's use of Xockets' patented DPU technology has allowed Nvidia to monopolize the field of GPU-enabled AI servers and Microsoft to monopolize the field of GPU-enabled AI platforms—and is critical to their success and market capitalization.”

The “illegal cartel” accusation relates to an entity called RPX, a patent risk management organization that Xockets says was “formed at the request of Big Tech companies to enable and create buyers’ cartels for intellectual property.”

The statement added that “every effort” had been made by Xockets to engage in “good-faith negotiations” with the two companies, but those efforts have thus far been rebuffed.

In addition to seeking damages for the patent infringement, Xockets is seeking an injunction to stop Nvidia from selling the products outlined in the lawsuit and releasing its upcoming Blackwell family of chips, whilst also stopping Microsoft from using Blackwell systems in its generative AI platforms.

“Xockets is also seeking damages to the fullest extent permitted by law,” the company said.

Neither Nvidia or Microsoft has issued a statement on the accusations. Nvidia declined to comment when approached by The Verge, while Microsoft didn't immediately respond to the publication's questions.