Anthropic and OpenAI Launch Cheaper Models in Same-Day Price War

On September 22, 2026, Anthropic and OpenAI simultaneously released new AI models with aggressive pricing, intensifying competition in the frontier AI market. Anthropic debuted Claude Opus 5.5, its flagship model featuring a 40% cost reduction compared to Opus 5, with input and output tokens priced at $4 and $20 per million respectively. The model generates output 30% faster than its predecessor while maintaining frontier-level capabilities. Concurrently, OpenAI released GPT-6 Sol and Luna, lighter-weight variants of its Astra system released three weeks earlier on September 3. Sol costs $2 per million input tokens and $10 for output, while the ultra-efficient Luna model prices at just $0.10 and $0.50—both representing 50% reductions from comparable GPT-5.6 tier pricing.