OpenAI slashes GPT-5.6 Luna price 80% amid AI price war

OpenAI and Anthropic slashed prices on mid-tier AI models in August 2026 as customers turn to cheaper alternatives from Chinese developers.

GPT-5.6 Luna, which OpenAI calls its "fastest and most affordable model", now costs 80 percent less. Anthropic launched Claude Opus 5 at half the price of its most capable model, Fable 5. Prices for models from leading US labs have fallen almost a quarter since mid-July 2026, according to Silicon Data's token price index.

The reductions mark a shift for US labs that have traditionally competed on performance rather than cost. Corporate AI users face rising bills as OpenAI and Anthropic shift some enterprise customers from flat subscriptions to usage-based billing. DoorDash and Airbnb have said they began using Chinese-made models to rein in costs, while Moonshot and DeepSeek have released increasingly capable open models that narrow the performance gap.

Tokens are the units of data processed by language models and used to calculate many bills. OpenAI reduced GPT-5.6 Luna from $1 to $0.20 per million input tokens and from $6 to $1.20 per million output tokens. Anthropic set Opus 5 at $5 per million input tokens and $25 per million output tokens. It also called off a planned price rise for Sonnet 5 that had been due to take effect in September 2026.

Benchmarking by Artificial Analysis found Opus 5 at medium effort delivered similar performance and cost per task to Moonshot's Kimi K3 at max effort. GPT-5.6 Luna at max effort performed similarly to DeepSeek's V4 Flash at max effort but cost just under twice as much per task. A person close to Anthropic said Opus 5's pricing below Fable 5 reflected how the startup's family of models is built, with no connection to competitors.

The price cuts come as OpenAI and Anthropic plot initial public offerings at trillion-dollar valuations, with investors seeking evidence that heavy AI spending can generate returns. Mantas Lukauskas, AI tech lead at website hosting provider Hostinger, said prices for the best models were flat to rising and the August 2026 changes are the first real test of whether US labs can protect the cost of their most advanced offerings.