Microsoft Booked $10B From OpenAI, 11% of Quarterly Sales

Microsoft said in its quarterly report, filed on 28 October 2026, that it earned $10.0 billion from business deals with OpenAI during the three months ending 30 September. This amount includes payments based on sharing revenue. Microsoft reported total revenue of $92.3 billion for the same quarter.

Based on our calculations, OpenAI accounted for about 10.8% of Microsoft’s total revenue during the quarter. For the financial year ending 30 June 2026, Microsoft’s annual report showed $24.1 billion in revenue from OpenAI out of $331.8 billion in total revenue. Based on our calculations, OpenAI accounted for about 7.3% of the yearly total.

What the Filing Discloses

Microsoft’s quarterly report, called Form 10-Q, says the company has an investment in OpenAI that gives it about a 24% ownership interest if all relevant shares are converted into ordinary shares. Because Microsoft accounts for this investment using the equity method, it treats OpenAI as a related party. The report therefore shows revenue and money owed to Microsoft from business with OpenAI.

According to the report, OpenAI owed Microsoft $7.2 billion on 30 September 2026, compared with $6.0 billion on 30 June 2026. Based on our calculations, the amount owed rose by $1.2 billion during the quarter. The September balance was equal to about 72% of the revenue Microsoft recorded from OpenAI during the quarter.

Compared With the Last Financial Year

Microsoft’s annual report gives a full-year figure of $24.1 billion in revenue from OpenAI for financial year 2026. Based on our calculations, that works out to an average of about $6.0 billion per quarter. The $10.0 billion recorded in the quarter ending in September was about two-thirds higher than that average.

The Investment Line

Microsoft reports gains and losses from its OpenAI investment separately from revenue, under other income or expenses. Its quarterly report says this category included a net gain of $272 million from OpenAI investments in the September 2026 quarter. In the same quarter a year earlier, it included net losses of $4.1 billion. Microsoft says the gains increased net income by $207 million, or $0.03 per share. A year earlier, the losses reduced net income by $3.1 billion, or $0.41 per share.

Microsoft’s non-GAAP financial figures leave out these investment gains and losses. Based on our calculations, the $272 million gain was about 0.6% of the company’s $46.0 billion in income before taxes for the quarter. A year earlier, the $4.1 billion loss was about 12% of the $34.3 billion in income before taxes.

Earlier reports showed larger amounts. Microsoft’s quarterly report for December 2025 recorded net gains of $10.0 billion for that quarter. Its annual report for financial year 2026 says the year’s net gains of $6.5 billion were mainly related to a gain from OpenAI’s recapitalisation, a change to its financial structure that reduced Microsoft’s ownership percentage.

Ownership and Funding

Microsoft’s quarterly report for September 2025 said that after OpenAI changed its financial structure, Microsoft owned about 27% of the new public benefit corporation, after accounting for possible share conversions and dilution. Under a new agreement, OpenAI had also agreed to buy an additional $250 billion worth of Azure services. The reports put Microsoft’s ownership interest at about 25% in June 2026 and about 24% in September 2026.

The reports say Microsoft committed to provide a total of $13 billion in funding. It had provided $11.6 billion by 30 September 2025 and $12.0 billion by 30 September 2026. Based on our calculations, about $1.0 billion remained to be provided.

Related Coverage

Our report on Microsoft’s full quarterly results covers the period in more detail: Azure grew 48% as Microsoft’s free cash flow fell to $18.6 billion. We also tracked Microsoft’s business backlog, which remained at $677 billion, and compared cloud profit margins at Google, Microsoft and AWS.

The Bigger Picture

Our reading of the reports shows a big difference between the two OpenAI-related figures. Microsoft recorded $10.0 billion in revenue from OpenAI during the quarter, but only $272 million in net gains from its investment in the company.

Based on our calculations, the amount OpenAI owed Microsoft rose by $1.2 billion during the quarter, reaching $7.2 billion. That was equal to about 72% of Microsoft’s revenue from OpenAI for the quarter.

The reports show that Microsoft’s ownership interest was about 27% after OpenAI changed its financial structure in October 2025, about 25% in June 2026 and about 24% in September 2026.

Three Important Points

FOR REVENUE Microsoft reported $10.0 billion in revenue from business deals with OpenAI during the quarter, including payments based on sharing revenue, according to its Form 10-Q. Based on our calculations, that was about 10.8% of Microsoft’s total revenue.

FOR THE BALANCE SHEET OpenAI owed Microsoft $7.2 billion on 30 September 2026, compared with $6.0 billion on 30 June, according to the report.

FOR EARNINGS The gains from Microsoft’s OpenAI investment increased net income by $207 million this quarter, according to the report. A year earlier, investment losses had reduced net income by $3.1 billion.

The Business Engineer View

This story fits the ideas in the Business Engineer framework called The AI Capex Map.

The framework argues: “The $1T capex cycle is being underwritten by a $1T concentrated demand commitment from two counterparties whose combined free cash flow is deeply negative.” It identifies those two companies as OpenAI and Anthropic. In simpler terms, it says that a huge wave of spending on AI infrastructure depends on large purchase commitments from two companies that, together, have strongly negative free cash flow.

Microsoft’s quarterly report now gives a figure for one side of this relationship: $10.0 billion in revenue from OpenAI in a single quarter. The framework was published in May 2026 and does not discuss this figure.

What the Report Does Not Establish

The report does not explain how the $10.0 billion is divided between cloud services and payments based on sharing revenue. It also does not explain why the amount increased. Microsoft did not report quarterly revenue from OpenAI for financial year 2026, so the comparison with the average for that year is only approximate.

The report says Microsoft calculates its share of income or losses from OpenAI using a method called hypothetical liquidation at book value. This means the investment figure is not simply Microsoft’s share of OpenAI’s profit or loss. Microsoft’s earnings announcement says it provides guidance about future results during its earnings call, but no information from that call is included here.

The Bottom Line

Microsoft reported $10.0 billion in revenue from business deals with OpenAI during the quarter ending 30 September 2026, including payments based on sharing revenue, according to its Form 10-Q. Based on our calculations, that was about 10.8% of Microsoft’s total revenue of $92.3 billion, compared with about 7.3% for financial year 2026. According to the report, OpenAI owed Microsoft $7.2 billion at the end of the quarter, up from $6.0 billion in June.

A note on sources: All figures related to OpenAI come from disclosures about related-party transactions, equity-method investments and other income in Microsoft’s Forms 10-Q for September 2025, December 2025, March 2026 and September 2026. The last of these reports was filed on 28 October 2026. Figures also come from Microsoft’s Form 10-K for financial year 2026. Our percentages, comparisons and averages are our own calculations. Earlier articles linked here have their own sources.

Sources: Microsoft Form 10-Q, quarter ending 30 September 2026 (filed 28 October 2026) · Microsoft FY2026 Form 10-K · Microsoft Form 10-Q, quarter ending 31 March 2026 · Microsoft Form 10-Q, quarter ending 31 December 2025 · Microsoft Form 10-Q, quarter ending 30 September 2025