Anthropic released Claude Opus 5.5 on Tuesday, claiming it performs at the level of its most advanced tool but at roughly 40 per cent lower cost. The San Francisco-based company positioned the new model as the first in a cost-efficient "family" aimed at winning a price war against Open AI and low-cost Chinese rivals ahead of its planned IPO this autumn.

Opus 5.5 will cost $4 per million input tokens and $20 per million output tokens, compared to Fable 5.1's $10 and $50 rates respectively. The model underwent extensive alignment testing and includes safeguards for high-risk areas like cyber security and biology, according to Anthropic.

The release comes as investors watch for signs that Anthropic can sustain its growth amid intensifying competition and price-sensitive customers. Open AI has recently slashed prices and claims to have the market's most powerful model, Astra, while Chinese "open-weight" models are gaining share, according to Vercel data.