On September 22, 2026, leading artificial intelligence labs Anthropic and OpenAI simultaneously released new flagship and efficiency models. Anthropic announced Claude Opus 5.5, cutting general workload execution costs by 40% compared to its previous version, while OpenAI introduced the budget-focused GPT-6 Sol and GPT-6 Luna with sharply reduced token pricing.
Key Takeaways
- Anthropic unveiled Claude Opus 5.5, cutting execution costs by 40% compared to Opus 5
- OpenAI launched mid-tier Sol and lightweight Luna using GPT-6 Astra training techniques
- GPT-6 Luna pricing drops to $0.10 per 1M input tokens and $0.50 per 1M output tokens
- Desktop app Free and Go tier users can now access GPT-6 Luna
- Speculation linking Anthropic’s launch timing to an upcoming IPO remains unconfirmed in official announcements
Claude Opus 5.5: 40% Cost Cut and Refined Writing
Released on September 22, 2026, Anthropic’s Claude Opus 5.5 reduces operational costs for general workloads by 40% compared to Opus 5. The model posted strong results across benchmarks for agentic coding, computer use, and knowledge work.
Opus 5.5 was tested by external red-teamers prior to rollout and includes the company’s highest safety standards. Writing performance was also tuned to produce clearer, more natural phrasing than the previous Opus 5 release.
OpenAI Introduces GPT-6 Sol and Luna with Lower API Prices
OpenAI launched the mid-range GPT-6 Sol and lightweight GPT-6 Luna on the same day. Built on training architectures from the flagship GPT-6 Astra, both models lower deployment expenses while maintaining high marks across coding, specialized knowledge tasks, factuality, and computer control.
Both models support a 1.05M token context window with maximum outputs up to 128K tokens. Key API specs and pricing include:
| Model | Input Price (1M tokens) | Output Price (1M tokens) | Cached Input Read | Knowledge Cutoff |
|---|---|---|---|---|
| GPT-6 Sol | $2 | $10 | $0.20 (90% discount) | April 20, 2026 |
| GPT-6 Luna | $0.10 | $0.50 | $0.01 (90% discount) | May 18, 2026 |
Compared to previous-tier models, GPT-6 Sol cuts input costs by 50%, while GPT-6 Luna slashes input costs by 50% and output costs by 58%.
Availability and Rollout Scope
GPT-6 Sol and Luna are rolling out across ChatGPT Work, Codex, and the OpenAI API for Plus, Pro, Business, Enterprise, and Edu tiers. In the desktop application, Free and Go users can also access GPT-6 Luna. The models have not yet arrived in the standard web Chat interface.
Granular condition differences across benchmark suites and rumors surrounding Anthropic’s reported November IPO timing were noted solely in media commentary and remain unverified in official company statements.
Sources
- pymnts.com
- vertexaisearch.cloud.google.com
- vertexaisearch.cloud.google.com
- vertexaisearch.cloud.google.com