India, July 29 -- Nearly 150 companies want no new restrictions on open-weight AI models, the kind anyone can download and modify. Their letter calls distillation - training a cheap model on a costlier one's answers - ordinary craft, not theft. The signatories include the who's who of the industry: OpenAI, Google, Grok-owner xAI. Most of them use distillation. Some have deeper stakes still. Meta's open Llama models undercut its closed rivals commercially at no cost to its ad-based business. Nvidia's Jensen Huang needs open ecosystems: a world of many small builders needs chips everywhere; a handful of closed labs needs them only in a handful of places.

And some have mixed motives. OpenAI, a signatory, has itself accused Chinese firm Deep...