OpenAI's annualized revenue $20 billion lower than prior investor estimates

OpenAI's ( OPAI.PVT ) annualized revenue is reportedly $20 billion short of prior estimates.

According to the Financial Times , the AI startup's annualized revenue topped out at roughly $50 billion as of September, well below the $70 billion outlets previously estimated .

The dramatic swing is a result of investor miscalculations. The FT said investors who initially cited the $70 billion figure arrived at the number by comparing OpenAI's revenue with Anthropic's ( ANTH.PVT ).

Annualized revenue takes a snapshot of revenue for a certain period and extrapolates it across a year. But OpenAI and Anthropic calculate their annualized revenue differently.

Investors initially tried to determine whether OpenAI's sales reached $40 billion in August. Later, when OpenAI told investors that revenue grew 70%, they added that amount to the initial $40 billion estimate and landed on $70 billion.

At $50 billion, OpenAI's annualized revenue would now fall below Anthropic's $65 billion in annualized sales.

OpenAI is widely anticipated to kick off its initial public offering sometime in early 2027, while Anthropic is rumored to hit the public market sometime before Thanksgiving, with its public S-1 investor prospectus expected to land any day now.

Both companies are battling for enterprise customers, offering up products including coding and general-purpose AI agents.

Last week, OpenAI held its annual developers conference, where it debuted its new Dots AI agents for enterprise workers and its latest model, GPT-6.1 Sol.

Email Daniel Howley at dhowley@yahoofinance.com. Follow him on Twitter at @DanielHowley .