Anthropic PBC accused Alibaba Group Holding Ltd. of conducting a large-scale campaign to illicitly access its Claude artificial intelligence model using approximately 25,000 fraudulent accounts between April 22 and June 5, 2026 [1, 2, 3].

The unauthorized activity involved around 28.8 million exchanges with Claude, targeting its most advanced features such as software engineering and agentic reasoning capabilities [4, 1, 2, 5, 3]. Anthropic described the campaign as a "distillation effort," where a less capable model is trained on outputs from a stronger one to replicate its performance [1, 2, 3].

Anthropic detailed the allegations in a letter dated June 10, 2026, sent to US Senators Tim Scott and Elizabeth Warren [1, 2, 3]. The company said Alibaba’s actions resemble earlier illicit distillation efforts by Chinese AI firms including DeepSeek, Moonshot, and MiniMax [1, 2, 3]. An Anthropic spokesperson said, "We believe combating the threat of illicit distillation requires coordinated action between government and industry, and we will continue working with Congress and the Administration to maintain American AI leadership" [2]. Their letter added, "These distillation attacks are carried out illicitly, systematically, and at an industrial scale to harvest US AI capabilities across frontier labs and repackage them as their own without incurring the training and R&D costs required to train US frontier models" [5].

Anthropic also claimed Alibaba ignored previous US government warnings about such distillation campaigns [2]. In April 2026, the White House accused China of industrial-scale intellectual property theft involving US AI labs’ technology [1, 3]. Alibaba was added to the Pentagon’s list of Chinese military companies in June 2026, a designation the company is currently challenging [1, 3]. Meanwhile, the US Commerce Department has delayed placing Chinese AI startup DeepSeek on a trade blacklist despite security concerns [1, 3].

The allegations against Alibaba impacted market confidence in Chinese AI firms. On June 25, 2026, Alibaba shares fell as much as 4.9%, hitting a 16-month low; the stock was down 33% year to date [6]. Other Chinese AI companies such as Xiaomi and Baidu also saw their shares decline by more than 3% on the same day [6].

Alibaba has not publicly responded to the accusations as of today [1, 2, 5, 3].