OpenAI, Anthropic Release Cheaper AI Models Days After Calling For 'Slowdown'

Amid calls from experts to slow down the rapid advancement in artificial intelligence (AI), OpenAI and Anthropic have unveiled cheaper models aimed at winning more business users. Both the releases were announced on Tuesday, with OpenAI introducing GPT-6 Sol and GPT-6 Luna, and Anthropic launching Claude Opus 5.5. The two AI giants released these models within hours of each other, as they try hard to fight the growing competition from low-cost AI models, especially from China and other cost-conscious business.

OpenAI's new models expand its GPT-6 lineup beyond the flagship GPT-6 Astra. Sol is positioned a tier below Astra and is designed for more demanding workloads, including coding and agentic tasks. Luna is aimed at high-volume, routine workloads such as extracting information and summarising documents.

Please welcome GPT-6 Sol and GPT-6 Luna to the GPT-6 universe.

GPT-6 Sol and Luna build on the advances behind GPT-6 Astra, bringing much of its strengths into faster and more affordable models to support work at scale.

We've also made caching and inference more efficient, and… pic.twitter.com/5LiVE4rbFt

— OpenAI (@OpenAI) September 22, 2026

The company has also cut API prices for the new models by 50 per cent compared with promotional pricing for GPT-5.6. OpenAI attributed the lower costs to improvements in inference and caching, saying the savings are being passed on to customers.

Anthropic's Claude Opus 5.5, meanwhile, is the first release in its new Claude 5.5 family. The company says it delivers performance comparable to its higher-end Fable 5.1 on most work, while costing around 40 per cent less to run than Opus 5. It is also more than 30 per cent faster, according to Anthropic.

The launches are notable because they follow recent calls from Anthropic CEO Dario Amodei and OpenAI CEO Sam Altman to slow or "pace" frontier AI development, largely to ensure safety measures can keep up with increasingly capable systems.

But the latest releases suggest the competition has shifted beyond simply building the most powerful AI. For OpenAI and Anthropic, making advanced models cheaper and more efficient is increasingly important as businesses weigh proprietary systems against cheaper open-weight alternatives.