Filed in New York on 13 March 2026, the complaint accuses OpenAI of using the reference publishers’ content as AI training data without permission, then generating responses that reproduce it verbatim, six months after the same companies sued Perplexity on nearly identical grounds.
Encyclopedia Britannica and Merriam-Webster have filed a copyright and trademark lawsuit against OpenAI in the US District Court for the Southern District of New York, alleging that ChatGPT has been trained on and continues to reproduce their copyrighted content without authorisation, to the material detriment of both publishers.
The complaint, filed on 13 March 2026 (case no. 1:2026cv02097), accuses OpenAI of using nearly 100,000 of Britannica’s online articles as training inputs for its AI language models. The full extent of the copying, the complaint acknowledges, is only known to OpenAI itself.
Britannica, which owns Merriam-Webster as a subsidiary, argues that the law does not permit OpenAI’s systematic disregard for its intellectual property rights and calls on it to account for the substantial harm it is causing and the profits it is reaping through that infringement.
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“ChatGPT then provides narrative responses to user queries that often contain verbatim or near-verbatim reproductions, summaries, or abridgements of original content, including plaintiffs’ copyrighted works.” – from the complaint.
The lawsuit is structured around two legal pillars, both of which mirror the framework the same plaintiffs used when they sued AI search engine Perplexity in September 2025. The first is copyright infringement under the Copyright Act of 1976, which gives authors the exclusive right to reproduce and distribute their works.
Britannica argues OpenAI violated those rights at multiple stages: by scraping its websites to create training inputs, by feeding that content into its models during training, and then by generating outputs that reproduce or closely summarise the originals when users query ChatGPT on topics covered by Britannica’s editorial catalogue.
The second pillar is trademark law under the Lanham Act. By presenting AI-generated responses, which may contain inaccuracies or hallucinations, alongside Britannica’s and Merriam-Webster’s famous trademarks and brand identities, the complaint argues that OpenAI misleads users into believing that Britannica or Merriam-Webster has endorsed or is the source of those responses.
Britannica’s reputation rests on accuracy built over more than 250 years; associating that brand with AI-fabricated information, the complaint contends, causes direct reputational harm that goes beyond copyright loss alone.
The business model under pressure
The underlying commercial argument follows the logic established in the broader wave of publisher lawsuits against AI companies. Britannica’s business today is primarily digital, built on subscriptions and advertising revenue that depend on web traffic.
When ChatGPT answers a user’s question about, say, the causes of the French Revolution or the properties of a chemical element using content sourced from Britannica’s articles, those users have less reason to visit Britannica’s website directly. The complaint describes ChatGPT as taking a free ride on Britannica’s trusted, high-quality content, shifting the value of that content to OpenAI without compensation.
Britannica discontinued its 32-volume print edition in 2012, fully pivoting to digital. That transition made the quality and exclusivity of its editorial content, produced by researchers, writers, and editors working to standards the brand has maintained since its founding in Edinburgh in 1768, the central asset of the business.
The complaint frames OpenAI’s alleged copying not merely as a legal violation but as an existential threat to a model that cannot survive if the economic returns from that content flow to AI platforms rather than to its creators.
The Perplexity precedent and what comes next
This is not Britannica’s first such case. In September 2025, the same plaintiffs, Encyclopedia Britannica and Merriam-Webster, filed an essentially parallel complaint against Perplexity, the AI-powered answer engine.
That complaint, also lodged in the SDNY, alleged that Perplexity’s system scraped Britannica’s content to build its responses in real time, bypassing robots.txt protections and presenting verbatim or near-verbatim reproductions under the guise of AI-generated summaries. The Perplexity case is still proceeding.
The OpenAI case is structurally similar, but arrives in a significantly more complex legal landscape. OpenAI is already the subject of a large multidistrict litigation (MDL) in the SDNY, currently overseen by Judge Sidney Stein, that consolidates more than a dozen copyright lawsuits brought by news publishers including the New York Times.
That MDL is approaching the close of fact discovery, with no fair use ruling expected before summer 2026 at the earliest. Analysts tracking the litigation landscape, including the ChatGPT Is Eating the World legal tracker, have noted that the Britannica-OpenAI case will very likely be transferred to that MDL and then stayed pending its outcome, meaning a resolution on the merits could be years away.
For now, the complaint brings the total number of copyright lawsuits filed against AI companies in the United States to 91, according to the same tracker. OpenAI had not publicly responded to the complaint at the time of writing.
The Britannica filing lands in a market where the legal and licensing approaches to AI content are diverging sharply. At the same time as publishers are suing, a growing number of media organisations have signed licensing deals with AI companies, News Corp signed a deal with Meta worth up to $50 million per year in March 2026; UK publisher Reach agreed a usage-based deal with Amazon for its Nova AI model the same month.
The Anthropic copyright case (Bartz v. Anthropic), involving the use of pirated books for AI training, reached a $1.5 billion class action settlement in 2025, the largest in the AI copyright litigation wave so far, establishing that these cases can produce significant financial consequences.
Whether Britannica’s lawsuit against OpenAI will follow the path of settlement, trial, or eventual consolidation into the MDL depends partly on the MDL’s own trajectory. What the filing makes clear is that publishers with strong brand equity and a defensible claim to accuracy, the encyclopaedias and dictionaries whose authority AI systems are arguably borrowing and monetising, are not content to wait for the industry to self-regulate.
