In a major escalation of the legal war between traditional knowledge institutions and AI giants, Encyclopedia Britannica and its subsidiary Merriam-Webster filed a lawsuit against OpenAI on Monday, March 16, 2026. The lawsuit, filed in Manhattan federal court, accuses the Microsoft-backed company of systematically “cannibalizing” centuries of curated human knowledge to build its artificial intelligence models.

The Allegations: Massive Scraping and Traffic Theft The plaintiffs claim that OpenAI unlawfully copied nearly 100,000 articles and thousands of dictionary definitions to train its GPT models. The core of their argument rests on two fronts:

• Copyright Infringement: The lawsuit alleges that ChatGPT produces “near-verbatim” copies of Britannica’s encyclopedia entries and Merriam-Webster’s definitions. By doing so, OpenAI is accused of shifting the value of this human-edited content to its own platform without compensation.
• Traffic Cannibalization: Britannica argues that by providing instant, AI-generated summaries of its copyrighted work, OpenAI is diverting users who would otherwise visit Britannica’s websites. This “free-riding” directly threatens the advertising and subscription revenue that funds their editorial staff.

Brand Reputation and “Hallucinations” Beyond copyright, the suit raises serious concerns regarding trademark infringement. Britannica—a brand with a 250-year reputation for accuracy—alleges that OpenAI’s chatbot often generates false information (known as “hallucinations”) and incorrectly attributes it to Britannica or Merriam-Webster. The plaintiffs argue that associating their trusted brands with AI-fabricated errors causes irreparable reputational harm.

A Pattern of Litigation This is not Britannica’s first legal battle in the AI space. The company filed a similar lawsuit against the AI search startup Perplexity AI in late 2025, which is still ongoing. OpenAI, meanwhile, faces a mountain of litigation from other major content creators, including The New York Times, various authors, and news publishers, who all argue that “fair use” does not cover the wholesale ingestion of their intellectual property.

The Defense While OpenAI has not yet issued a formal response to this specific filing, the company has consistently maintained that training AI models on publicly available internet data is a “transformative” use protected under fair use laws. OpenAI has also increasingly sought to sign individual licensing deals with publishers, though Britannica’s lawsuit suggests that a middle ground has not yet been reached between the two heritage brands and the AI pioneer.

The outcome of this case could set a vital precedent for whether AI companies must pay for the “truth” they extract from the world’s most trusted reference materials.