OpenAI has told investors that its annualised revenue for September was nearly $50 billion, significantly short of the $70 billion it had previously suggested, Reuters has reported.

A person familiar with the matter told the newswire that the discrepancy mainly arose as an attempt to draw a direct comparison with rival AI developer Anthropic.

The $50 billion figure was first reported by the Financial Times.

Annualised revenue is a way of estimating annual revenue by multiplying one month’s income by 12. It is used by several major AI players, including Anthropic and OpenAI, but has faced criticism from analysts and critics for allowing companies to potentially cherry-pick numbers.

As it is not a standardised accounting practice, the figure can also be calculated in different ways. OpenAI, for instance, does not include revenue from sales via cloud partners such as Google Cloud or AWS, while Anthropic does, according to reporting by the FT and Reuters.

This may not present investors with a full picture of a company’s financial situation, and is subject to change.

OpenAI claims to have begun the year with annualised revenues of $20 billion, a large growth from its $6 billion in 2024. However, it has fallen behind Anthropic’s reported annualised revenues, which reached over $10 billion in the second quarter of this year.

Anthropic has also fallen short of revenue projections recently. Its initial public offering (IPO) prospectus, seen by Reuters last month, reported a real revenue of nearly $4.6 billion in 2025, seemingly short of the $10 billion revenue the company reported in May.

Both Anthropic and OpenAI are hoping to IPO in the next year, which will provide the public the first look at their actual costs and revenues.

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