Encyclopedia Britannica and Merriam-Webster sue OpenAI for unauthorized use of copyrighted content
Encyclopedia Britannica and Merriam-Webster sued OpenAI on 13 March 2026 alleging unauthorized use of approximately 100,000 copyrighted articles and definitions to train ChatGPT and GPT-4. The plaintiffs claim ChatGPT reproduces their content nearly verbatim, diverting users and revenue while damaging their reputations through false attributions.
What happened
Encyclopedia Britannica and its subsidiary Merriam-Webster filed a lawsuit against OpenAI in Manhattan federal court on 13 March 2026, alleging that OpenAI unlawfully used approximately 100,000 articles, encyclopedia entries and dictionary definitions to train the language models powering ChatGPT.
According to the complaint, ChatGPT reproduces Britannica and Merriam-Webster content 'nearly word-for-word' rather than producing transformative outputs, contradicting OpenAI's fair use defense.
Reported impact
The plaintiffs claim that ChatGPT's near-verbatim reproduction of their content answers user questions directly, preventing users from visiting their websites and causing significant loss of revenue.
Britannica further alleges that ChatGPT attributes false information generated by the model's hallucinations to Britannica as a source, damaging the organization's credibility and trademark.
Index analysis
OpenAI stated that its models enhance innovation, were trained on publicly available data, and rely on fair use principles because the technology is transformative and does not produce copies of original works.
The dispute centers on whether web scraping and incorporation of copyrighted content into training datasets constitutes fair use when the resulting model can reproduce source material with high fidelity.
Governance controls
Britannica seeks a court injunction to prevent further misuse of its content and seeks damages from OpenAI, though the amount is unspecified.
Britannica has also filed suit against Perplexity AI, with that case remaining ongoing.
Classification
Sources and evidence
This record was researched and written by the Index, based on the following original reporting.