Reddit (NASDAQ: RDDT) has filed a lawsuit against AI startup Anthropic, the developer of the Claude chatbot, accusing it of unlawfully using Reddit’s platform and user-generated content to train its AI models without a license or consent. The lawsuit was filed on a Wednesday in California’s San Francisco Superior Court. Following the announcement, shares of Reddit surged, with one report indicating a jump of 7.35% to close at US$118.21 on the day, and another noting a surge of close to 7%, contributing to an approximate 28% climb for the stock in 2025 so far.

The complaint alleges that Anthropic scraped Reddit’s servers more than 100,000 times since July 2024. This activity purportedly continued even after Anthropic informed Reddit it had ceased such actions, or, as another account states, despite claiming to have blocked its bots from doing so in July 2024. Reddit contends these actions constitute a breach of its user agreement, which explicitly bars companies from “commercially exploit[ing]” users’ data without a formal deal, and describes them as “unfair and unlawful business acts.” The legal filing asserts that Anthropic “is in fact intentionally trained on the personal data of Reddit users without ever requesting their consent.” Reddit's complaint also characterized Anthropic as a “late-blooming” company presenting itself as a “white knight of the AI industry” while disregarding the platform’s rules.

Reddit underscored the immense value of its content, describing its platform as hosting “nearly 20 years of rich, human discussion on virtually every topic imaginable.” Ben Lee, Reddit’s Chief Legal Officer, stated that Reddit’s “humanity is uniquely valuable in a world flattened by AI,” and emphasized that companies like Anthropic do not have the right to exploit this data for profit without compensation. Lee added, “We will not tolerate profit-seeking entities like Anthropic commercially exploiting Reddit content for billions of dollars without any return for redditors or respect for their privacy.” In contrast to Anthropic's alleged actions, Reddit has established content licensing agreements with other major tech companies, including ChatGPT developer OpenAI and Alphabet's Google, which incorporate specific terms to protect user privacy, such as requiring the removal of users’ deleted posts from their training systems. Reddit claims Anthropic “refused to engage” in licensing negotiations and ignored multiple requests to halt its scraping activities.

The lawsuit's primary focus is on breach of contract and violation of Reddit's terms of service, rather than copyright infringement, which has been the central claim in other AI-related lawsuits, such as those initiated by The New York Times and various authors. Reddit specifically alleges that Anthropic disregarded its robots.txt file, a standard web protocol used to instruct bots on site crawling restrictions. In its suit, Reddit is seeking compensatory damages for the value of the content it claims Anthropic used, restitution of any unjust enrichment, and a court injunction. This injunction would require Anthropic to remove “any technology derived from Reddit content,” which could potentially impact the Claude chatbot. Reddit is also requesting a jury trial.

In response to the allegations, an Anthropic spokesperson stated, “We disagree with Reddit's claims and will defend ourselves vigorously.” Anthropic, which has received backing from major investors like Amazon and Google, had previously acknowledged Reddit as a source of high-quality data in a 2021 paper. Reddit's complaint argues that Claude was trained on its data despite these prior acknowledgements and repeated warnings. The filing states, “Anthropic refuses to respect Reddit’s guardrails. It believes it is entitled to take whatever content it wants and use that content however it desires, with impunity.” This legal action occurs amidst a wider trend of litigation against AI companies, with firms like OpenAI, Meta, and Cohere also facing lawsuits from news publishers, authors, and other content creators regarding the use of training data. Anthropic itself has previously faced legal challenges from authors and music publishers concerning alleged use of copyrighted material.

This lawsuit also highlights Reddit's increasingly significant position within the AI ecosystem, particularly as a valuable source of content for large language models (LLMs). Since its public offering in March 2024, Reddit has actively pursued monetizing its data, securing a reported US$60 million per year deal with Google and forging a separate partnership with OpenAI. Notably, OpenAI CEO Sam Altman has an 8.7% stake in Reddit and previously served on its board. With a current market capitalization of approximately US$22 billion, the outcome of Reddit's lawsuit against Anthropic could establish an important precedent for how online platforms can assert control over their data and negotiate compensation in an era increasingly dominated by artificial intelligence.