Alibaba fell to a 16-month low in Hong Kong after Anthropic reportedly accused the company of illicitly accessing its Claude AI models. Shares dropped as much as 4.9% on Thursday, extending Alibaba's 2026 decline to 33%. Its U.S.-listed shares also fell 3% on Wednesday. The pressure spread to other Chinese AI names, with Baidu and Xiaomi both dropping more than 3%. Bloomberg reported that Anthropic sent a letter to White House officials and U.S. senators alleging Alibaba was involved in an industrial-scale effort to access Claude. Anthropic described the activity as distillation, where a smaller model is trained using outputs from a more powerful model. The accusation reportedly involved operators linked to Alibaba and Qwen, Alibaba's AI lab. Anthropic has previously claimed Chinese AI firms, including DeepSeek, tried to extract capabilities from Claude.