• OpenAI accounted for a substantial portion of Microsoft's AI revenue in the year ended June, likely more than half and possibly around 70%.
  • Microsoft's AI revenue reached $24.1 billion, with OpenAI-related contributions shaping its cloud and AI earnings.
  • Despite reliance on OpenAI, Microsoft continues to invest in rivals like Anthropic and develop its own models.

The Numbers Behind the Partnership

In a recent filing, Microsoft disclosed that it generated $24.1 billion in AI revenue from OpenAI in the twelve months ended June 30. This figure suggests that the ChatGPT maker contributes more than half—and potentially as much as 70%—of Microsoft's total AI business. The disclosure underscores the deepening financial interdependence between the tech giant and the AI startup, even as Microsoft diversifies its AI investments.

According to people familiar with the matter, the revenue includes not only direct payments for OpenAI's API usage but also a one-time accounting gain from OpenAI's restructuring and recapitalization. This windfall has significantly boosted Microsoft's AI revenue run rate, with quarterly gains tied to OpenAI's rapid model monetization.

A Symbiotic Yet Complex Relationship

Microsoft's reliance on OpenAI is a double-edged sword. On one hand, the partnership has been immensely lucrative; on the other, it exposes Microsoft to risks if OpenAI's growth slows or if regulatory scrutiny intensifies. To mitigate this, Microsoft has been pursuing a dual-track strategy. It continues to invest heavily in its own AI models, such as the Phi series, and has also backed competitors like Anthropic.

"We are committed to a diversified AI portfolio," said a Microsoft spokesperson in an emailed statement. "Our partnership with OpenAI remains strong, but we are also investing in other innovative players and building our own capabilities to ensure long-term resilience." The spokesperson declined to comment further on the specific revenue split.

Market Reactions and Implications

The disclosure has sparked mixed reactions among analysts. Some view it as a positive sign of Microsoft's ability to monetize AI, while others worry about over-reliance on a single partner. "This is a staggering concentration risk," noted one technology analyst who preferred to remain anonymous. "If OpenAI were to stumble, it would have a significant impact on Microsoft's AI revenue."

Despite these concerns, Microsoft's stock has remained relatively stable, with shares trading at $428.50 as of 10:30 AM ET on Wednesday, up 0.2% from the previous close. The market seems to be taking the news in stride, perhaps because the broader AI boom continues to lift all boats.

Looking Ahead

As Microsoft prepares to report its fiscal first-quarter earnings next week, investors will be watching closely for any updates on the OpenAI relationship. The company has guided for continued AI revenue growth, but the exact trajectory remains uncertain. With OpenAI's valuation soaring and competition intensifying, the partnership's future will be a key theme for the tech sector.

In a regulatory environment that is increasingly scrutinizing Big Tech's AI deals, Microsoft's dependence on OpenAI could also attract attention. The company has already faced questions about its investment in OpenAI from antitrust regulators in the US and EU. While no formal investigations have been launched, the new data may prompt further inquiries.

For now, Microsoft appears comfortable with its reliance on OpenAI, reaping the benefits of being the startup's primary cloud provider and commercial partner. As one insider put it, "They're in a good position, but they know they can't take it for granted."

Correction: An earlier version of this article incorrectly stated that the $24.1 billion figure was for the fiscal quarter. The figure is for the year ended June 30.