NVIDIA, Microsoft and 25 groups back open-weight AI models to lawmakers as OpenAI sits out

In a coordinated push, NVIDIA, Microsoft and 25 groups signed a letter to lawmakers defending open-weight AI models. Jensen Huang made it his first-ever X post: 'AI will transform every industry, power every company, and be built by every country. Open models strengthen safety and cybersecurity, accelerate innovation and diffusion, and enable sovereignty.' Satya Nadella, Sundar Pichai (citing Google's Gemma, which just crossed 300M downloads), Mistral's Arthur Mensch, Thinking Machines' Mira Murati and Perplexity's Aravind Srinivas all publicly co-signed the sentiment. Srinivas called it 'the most positive I have felt about the future of American AI.'

The mechanics are as much politics as technology: the letter frames open weights as essential to American competitiveness and national security, a direct response to Chinese open models (GLM, Kimi K3, DeepSeek) gaining US traction. Critics note the advocacy is partly self-interested — open-model adoption expands GPU demand, directly benefiting NVIDIA and cloud providers.

The telling absences drove the story's edge. Sam Altman offered only lukewarm support ('i want the US to win in AI both in open source and proprietary models'), and OpenAI did not sign. More pointedly, Anthropic refused to sign the letter, triggering a 457-upvote r/Anthropic thread and heated debate about the company's stance on openness — awkward timing given its Opus 5 launch the same week. The split reveals the two frontier labs most associated with closed models both declining to endorse open weights, while the hardware and enterprise-cloud camp lines up firmly behind them.