Britannica and Merriam-Webster have filed a lawsuit against OpenAI, alleging that the AI giant has built its $730 billion company on the back of their researched content.

In a filing submitted to the Southern District of New York, the companies accuse OpenAI of cannibalizing the traffic and ad revenue that publishers depend on to survive. “ChatGPT starves web publishers, like [the] Plaintiffs, of revenue,” the complaint reads.

Where a traditional search engine sends users to a publisher’s website, Britannica and Merriam-Webster allege ChatGPT instead absorbs the content and delivers a polished answer. It also alleges the AI company fed its LLM with researched and fact-checked work of the companies’ hundreds of human writers and editors.

The case is the latest in a series accusing AI firms of data theft, raising questions about what counts as public knowledge and what information online should be off-limits for AI use.