The companies warned against what they described as "premature restrictions" on open-weight AI, saying open models help broaden access to AI technologies instead of concentrating capabilities among a small number of providers.
“Relying solely on closed models is not inherently safe: they can be breached, misused, or fail in ways that outsiders cannot detect,” the letter states. “And concentrating advanced AI capabilities behind a small number of closed models compounds that risk.”
The group also argued that policymakers should distinguish between unlawful intellectual property theft and legitimate AI development practices. It said concerns around illegal distillation should be addressed through targeted legal and commercial measures rather than broad limits on model-development techniques.
“Policymakers should be careful not to conflate legitimate model-development techniques with misappropriation. Distillation, or the practice of using one model's outputs to help train or improve another, is a widely used technique for model improvement, evaluation, and validation.”
The debate has intensified following the release of Moonshot AI's Kimi K3 model, which has drawn attention for its performance on industry benchmarks. U.S. officials have also raised concerns over whether Chinese AI companies have used American intellectual property to develop competing systems.
Treasury Secretary Scott Bessent recently said the Trump administration would examine whether Chinese companies were stealing U.S. intellectual property and noted the government has "the ability to sanction them because of this theft."
White House advisor Michael Kratsios separately said Moonshot AI developed Kimi K3 by distilling Anthropic's technology. While describing legitimate AI distillation as an important part of open innovation, he wrote that "large-scale, covert industrial distillation aimed at stealing proprietary U.S. technology" is "unacceptable."
The signatories maintained that restricting open-weight models would not improve security. Instead, they argued that defenders need access to advanced AI systems alongside attackers.
“The right response to this risk is not to prohibit open weights. In a world where cybersecurity attackers use advanced AI, defenders need access to models with comparable capabilities so they can detect, simulate, and respond to emerging threats.”
Beyond opposing broad restrictions, the companies called for greater investment in the open AI ecosystem. Their recommendations include expanding compute access for startups and researchers and supporting shared datasets and evaluation frameworks.
Nvidia CEO Jensen Huang and Microsoft CEO Satya Nadella shared the letter on social media. Elon Musk also endorsed it publicly, writing that it has his "full support," although SpaceX was not among the official signatories.
Notably absent from the letter were OpenAI and Anthropic, two companies that primarily develop closed AI models. Greg Brockman, OpenAI's president, said he supports broad access to AI and that he has not participated in discussions with the Trump administration about banning Chinese open-weight models.
“I think that, that fundamentally, AI and AI usage is something that is actually very important to democratize,” Brockman said. “And so, for me, at a sort of deep level, I think that having more models, more usage, that is a good thing.”
The letter concludes by arguing that the United States' leadership in AI will depend on building a broad and competitive ecosystem rather than relying on a small number of frontier models.
“Our AI leadership will be judged not by one frontier AI model, but by whether the United States builds a strong, open ecosystem that diffuses into every sector,” the letter says. “This is essential for creating opportunities for innovation and prosperity across the country.”
This analysis is based on reporting from CNBC.
Image courtesy of Jeffrey Dastin/Reuters.
This article was generated with AI assistance and reviewed for accuracy and quality.
