Google and OpenAI File Legal Brief Backing Anthropic in Antitrust Case

Google and OpenAI’s joint brief, filed in the U.S. District Court for the Eastern District of Virginia, argues that the Justice Department’s antitrust complaint against Anthropic rests on a “misreading of market dynamics” and that the startup’s competitive posture actually benefits consumers, Gizmodo reports. The filing, signed by senior counsel from both firms, contends that Anthropic’s recent partnership with Microsoft and its open‑source model “expand the ecosystem rather than constrict it,” positioning the company as a counterweight to the dominance of larger players such as Google’s Gemini and OpenAI’s GPT‑4.

The brief also points to Anthropic’s rapid growth in enterprise contracts and its commitment to safety‑first research as evidence that the firm is “not a monopoly‑seeking entity” but a “vital source of innovation” in the generative‑AI market. According to the filing, the DOJ’s claim that Anthropic’s licensing agreements with Microsoft create an “exclusionary barrier” is “unsubstantiated,” because the agreements are “non‑exclusive and subject to standard termination clauses,” Gizmodo notes.

OpenAI’s chief legal officer, in a brief statement to Gizmodo, said the company “supports any legal argument that preserves a level playing field for all AI innovators.” Google’s counsel echoed the sentiment, emphasizing that “robust competition drives better products and safeguards against concentration of power.” Both firms warned that a precedent of penalizing collaborative licensing could “chill future partnerships across the sector,” potentially slowing the rollout of safety‑critical features that Anthropic has championed.

Industry observers, while not quoted directly in the source material, have flagged the case as a bellwether for how regulators will treat the increasingly intertwined web of AI alliances. The brief’s timing—just weeks after the DOJ’s complaint—suggests that Google and OpenAI are positioning themselves as defenders of a “healthy, competitive market” rather than as targets of the same scrutiny. As Gizmodo points out, the filing does not address the broader question of whether the three firms collectively hold “too much market power,” leaving that debate for the courtroom.