Nvidia is buying the open-source AI platform Hugging Face for about $13 billion, a sign the chipmaker wants to own the software and developer side of AI too — good for Nvidia's grip on the industry, worrying for rivals.

• Nvidia agreed to buy Hugging Face, the place where most AI developers share and download open models.
• Jensen Huang says the platform will stay open to everyone and that open-source models make AI safer and easier for countries to control themselves.
• It is Nvidia's second-biggest deal ever, behind the $20 billion purchase of chipmaker Groq's assets last December.
• Hugging Face's chief executive says he made the first move over the summer and the deal came together in weeks.
• The message is that Nvidia is no longer just a chip company — it now owns a big piece of the AI software stack.

Outlook: Expect regulators and rivals to look hard at how much of the AI pipeline one company now controls.