OpenAI and Anthropic cut model API prices in same-day releases

On 22 September 2026 OpenAI and Anthropic shipped new models within an hour of each other and slashed API prices. GPT-6 Luna costs $0.10/$0.50 per million tokens, GPT-6 Sol $2/$10, while Claude Opus 5.5 dropped 20% to $4/$20 with cache reads down 60%.

• GPT-6 Luna: $0.10 per million input tokens, $0.50 per million output
• GPT-6 Sol: $2/$10 per million tokens, about half GPT-5.6 pricing
• Claude Opus 5.5 cut 20%, from $5/$25 to $4/$20 per million tokens
• Anthropic cache-read pricing fell 60% for agentic workloads