The AI Price War: Claude Opus 5.5 vs GPT-6 Sol and Luna
On September 22, Anthropic launched Claude Opus 5.5 at roughly 40% lower cost than Opus 5, and about 90 minutes later OpenAI answered with GPT-6 Sol and Luna at half of last generation’s prices. Full breakdown in the slides above. Sources: Simon Willison (simonwillison.net), AI Explainer India, Intelligibberish, AI Briefing Room citing Reuters — September 22–26, 2026.