Anthropic and OpenAI launch new models on the same day in AI price war

On September 22, 2026, Anthropic released Claude Opus 5.5 while OpenAI countered with GPT-6 Sol and GPT-6 Luna, both focused on lower pricing. Opus 5.5 costs $4/$20 per million tokens (20% below Opus 5), GPT-6 Sol is $2/$10, and GPT-6 Luna is $0.10/$0.50.

• Claude Opus 5.5: $4/$20 per million tokens, cache reads down 60% to $0.20
• GPT-6 Sol: $2/$10 per million tokens; GPT-6 Luna: $0.10/$0.50
• Opus 5.5 scored 66.4% on Terminal-Bench 4.0 vs 57.9% for GPT-6 Astra
• Anthropic claims 40% lower cost on typical workloads versus Opus 5