OpenAI priced its new model at exactly half of Anthropic's, hours after Anthropic launched

The competition between the top AI labs has stopped being only about capability. On Tuesday it became explicitly about price, and the timing left no doubt it was deliberate.

Anthropic released Claude Opus 5.5. Within hours, OpenAI released two new models, GPT-6 Sol and GPT-6 Luna — and priced them to undercut, precisely.

The Numbers

Anthropic set Opus 5.5 at $4 per million input tokens and $20 per million output tokens, about 20 per cent below its previous rates.

OpenAI set GPT-6 Sol at $2 per million input and $10 per million output — exactly half of Opus 5.5, on both figures. Its budget model, GPT-6 Luna, came in at $0.10 input and $0.50 output, undercutting the low-cost open-weight models from China that had competed mainly on price. In one announcement, OpenAI moved against a premium rival and a cheap one at once.

Why 'Exactly Half' Is A Message

Pricing a product at precisely half a competitor's, on the same day that competitor launches, is not a coincidence of cost accounting. It is a signal aimed at the people who pay AI bills.

It tells buyers there is no price reason to prefer the rival, and it tells the rival that OpenAI will use its scale and capital to set the ceiling. OpenAI is the most valuable private AI company in the world, and it is spending some of that advantage on making capability cheap enough that price stops being a reason to shop elsewhere.

What It Means For Buyers

For anyone building on these models, this is straightforwardly good in the short term.

The cost of frontier-level AI is falling fast, and falling because the largest player has decided to compete on it. Tasks that were marginal at last year's prices become viable at this year's. A company comparing providers now has genuine leverage, because nobody can afford to be the expensive option.

The Question Underneath

The harder question is whether prices this low are sustainable, and it deserves scepticism rather than celebration.

Running these models costs real money — in chips, power and data-centre capacity — and the companies setting these prices are, for the most part, not yet profitable on the underlying economics. Pricing at half a competitor can be a durable advantage built on genuine efficiency, or it can be a subsidy funded by investors betting on future dominance. From the outside, the two look identical until the funding environment changes.

History offers the caution. Markets where a dominant player prices below cost to win share tend to see prices rise once the field has thinned. Cheap frontier AI is a real benefit today; assuming it is permanent is a different bet.

The Context That Makes It Sharper

This price war arrives as both OpenAI and Anthropic move toward public listings, each valued privately near a trillion dollars.

A company about to sell shares has reason to demonstrate dominance, and undercutting a rival on launch day is a vivid way to do it. Some of this pricing serves the customer; some of it serves the story the sellers need to tell investors. Telling the two apart is now part of a buyer's job.

What To Watch

Whether prices keep falling or stabilise once the launch dust settles. Whether the cuts pressure the open-weight model makers, whose main advantage was cost, into a corner. And whether any of these rates rise after the IPOs, when the pressure shifts from winning share to showing profit.