Anthropic and OpenAI released new artificial intelligence models on September 22, 2026, just 10 days after their CEOs advocated for a slowdown in AI development. Anthropic launched Claude Opus 5.5, while OpenAI introduced GPT-6 Sol and GPT-6 Luna. Both companies focused on price reductions rather than increasing model capabilities.
Anthropic released Claude Opus 5.5 at 16:31 UTC. The model matches the performance of Claude Fable 5.1 on most tasks while reducing operational costs by 40% compared to the previous Opus 5 version. List prices for input tokens dropped to $4 per million, and output tokens to $20 per million. The model underwent safety reviews by METR and Frontier Design.
OpenAI launched GPT-6 Sol and GPT-6 Luna at 18:12 UTC, both based on the GPT-6 Astra architecture. The company reduced developer prices by 50% compared to GPT-5.6 promotional rates. GPT-6 Sol costs $2 per million input tokens, while Luna is priced at $0.10. Paid ChatGPT users have immediate access to both models, and free users can access Luna via the desktop app.
The recent releases follow a public call by Anthropic CEO Dario Amodei on September 12, 2026, to prioritize model alignment and safety. OpenAI CEO Sam Altman and Elon Musk previously supported this initiative. Despite the slowdown pledge, neither company has provided a timeline for releasing models that exceed their current flagship capabilities.
