The filing came out in late July. The figures drew fresh attention on September 22, when The Motley Fool argued that Microsoft's biggest AI customer is also its biggest risk. That argument needs careful handling. Some of the ratios now circulating are reasonable estimates, some are loose comparisons, and part of the partnership framing is out of date because the terms changed in April.
What Microsoft actually disclosed
Start with what Microsoft reports directly and what other people have calculated from it.
| Measure | Figure | Basis |
|---|---|---|
| Revenue from commercial arrangements with OpenAI | $24.1 billion | Reported in the FY2026 10-K |
| Accounts receivable from OpenAI | $6.0 billion | Reported, as of June 30, 2026 |
| Total Microsoft revenue | $331.8 billion, up 18% | Reported |
| Azure revenue | More than $100 billion, up 41% | Company statement (no exact figure given) |
| Microsoft Cloud revenue | $214.4 billion, up 27% | Reported |
| Commercial remaining performance obligation | $678 billion, up 84% | Reported |
| OpenAI share of total revenue | About 7% | Calculated ($24.1B ÷ $331.8B ≈ 7.3%) |
| OpenAI share of Azure | "About a quarter" | Loose comparison (see below) |
On the 7% figure, The Motley Fool noted that Microsoft's total revenue for fiscal 2026 (the 12 months ended June 30) was $331.8 billion, up 18% year over year. OpenAI alone contributed about 7% of it. It also pointed out that no other customer is identified, or given a number, in the filing. The publication added that Microsoft doesn't rank its customers, and it says that none made up more than 10% of revenue.
A note on wording: some coverage says OpenAI "owed" Microsoft $6 billion. In accounting terms that is accounts receivable, meaning billed or earned money Microsoft expects to collect. It is normal for any large customer relationship and says nothing about whether the payments are overdue.
Section summary: Microsoft's audited filing supports the $24.1 billion revenue figure and the $6 billion receivable. The percentages are calculations by outside analysts, not disclosures from Microsoft.
Why "a quarter of Azure" needs an asterisk
The comparison that got the most attention comes from The Motley Fool: Azure, Microsoft's cloud computing platform, topped $100 billion of revenue for the first time in fiscal 2026, growing 41% year over year. OpenAI's arrangements alone equaled about a quarter of that.
"Equaled" is carefully chosen, and it matters. The $24.1 billion is not all Azure revenue. As Neowin noted, the filing does not provide a breakdown of the $24.1 billion figure. The revenue may include Azure cloud services purchased by OpenAI, revenue-sharing payments linked to OpenAI products, and revenue from other commercial agreements. So, we can't interpret this number as Microsoft's share of OpenAI's revenue or as Azure revenue alone.
Techzine said much the same: Microsoft typically reports at the segment level, where OpenAI-related revenue is included in the broader Azure and Intelligent Cloud figures.
The ratio compares two numbers of the same size, but the true OpenAI share of Azure could be noticeably lower. That depends on how much of the $24.1 billion comes from revenue sharing rather than compute. Microsoft doesn't say.
Microsoft also doesn't reveal the margins. Yahoo Finance's analysis points out that Microsoft does not separately disclose the profit generated by those OpenAI commercial arrangements. It also notes that Microsoft Cloud gross margin fell to 66%, with management citing continued AI-infrastructure investment and growing AI product usage. Cloud compute sold to a single hyperscale AI lab is a very different business from high-margin Microsoft 365 seat licenses.
The ownership side: 27% then, about 25% now
Microsoft is OpenAI's cloud supplier, but it is also a major shareholder. After OpenAI's recapitalization in October 2025, Microsoft said it held a stake valued at about $135 billion, roughly 27% of OpenAI Group PBC on an as-converted diluted basis. Neowin adds that before the restructuring, Microsoft held a 32.5% stake.
That 27% figure is already out of date. According to Yahoo Finance's reading of the filing, Microsoft also owns an around 25% interest in OpenAI on an as-converted basis. The 10-K says the stake shrank during the year because of the recapitalization and later funding rounds, and Microsoft recorded dilution gains as a result. Neowin also reported that Microsoft also confirmed that it has committed a total of $13 billion to OpenAI, of which $11.9 billion had been funded as of June 30.
The equity stake is also moving Microsoft's reported profits. Microsoft recorded $5.0 billion of net-income benefit from net gains on its OpenAI investments. Microsoft now excludes OpenAI's impact from its non-GAAP earnings to separate that effect out.
Section summary: Microsoft is exposed to OpenAI in two ways at once: through revenue, as a supplier, and through equity, as a shareholder with about a quarter of the company.
The partnership terms changed in April 2026
This is where some coverage, including parts of the NeoTeo framing, falls behind. The October 2025 agreement gave Microsoft an exclusive IP license through 2032. It also secured OpenAI's commitment to buy an additional $250 billion in Azure services. Microsoft's right of first refusal to be OpenAI's compute provider ended at that point.
Then, in April, the partnership was revised once again. Under the amended terms announced by Microsoft on April 27, 2026:
- Cloud: Microsoft remains OpenAI's primary cloud partner. OpenAI products ship first on Azure unless Microsoft can't, or chooses not to, support the required capabilities. OpenAI is now permitted to offer its products through any cloud provider. This opened the door for Amazon, which now offers OpenAI models via Bedrock.
- IP: Microsoft's license to OpenAI model and product IP still runs through 2032, but it is now non-exclusive.
- Revenue share: Microsoft no longer pays revenue share to OpenAI. OpenAI's payments to Microsoft continue through 2030 at the same percentage, subject to a total cap and no longer tied to technological progress.
- Equity: Microsoft keeps participating in OpenAI's growth as a major shareholder.
The 10-K describes the relationship calmly: "In October 2025 and April 2026, we extended this partnership... Microsoft is a major investor in OpenAI and will continue to receive revenue-sharing payments. We hold rights to OpenAI's intellectual property, including models and infrastructure, for integration into our products."
For IT pros, the takeaway is that Microsoft's exclusive access to OpenAI is over. Microsoft is still first in line, but it's no longer the only one.
Where concentration actually bites: the backlog
The revenue figure gets the headlines. The contracted backlog carries more of the risk. Commercial remaining performance obligation (RPO), meaning contracted revenue not yet recognized, rose 84% to $678 billion. On the July 29 earnings call, CFO Amy Hood said RPO grew 25% excluding OpenAI. The Motley Fool summed it up: Microsoft's commercial backlog grew 84% to $678 billion last fiscal year, but only 25% excluding OpenAI.
That gap between 84% and 25% shows how much of Microsoft's future booked revenue depends on one customer. It's also spending huge amounts building infrastructure for a customer that reportedly spends much more cash than it brings in.
Before anyone panics, here is Microsoft's side of the picture:
- Hood said roughly 30% of total RPO should turn into revenue over the next 12 months, and the weighted average duration is 2.3 years.
- She said nearly 90% of Microsoft Cloud's revenue of more than $214 billion came from customers outside "frontier model companies."
- Microsoft said Azure demand still exceeded available capacity. Azure and other cloud services grew 43% in the fourth quarter.
A 25% growth rate in backlog without OpenAI would be a strong result for most companies. The risk is concentration. That is not the same as predicting a default, and nothing in the disclosures suggests OpenAI is missing payments or that Microsoft expects a specific loss.
Hedging in plain sight: Microsoft's model strategy
Microsoft is not quietly leaving OpenAI. It is making sure OpenAI can be replaced if needed. On the earnings call, Satya Nadella described a catalog of more than 11,000 models, including OpenAI, Anthropic, Mistral, xAI and Microsoft's own MAI family. He reported a fivefold increase since the start of the year in customers building with models from multiple providers.
He framed the goal as a system where "every model is substitutable." Microsoft now runs in-house MAI models inside GitHub Copilot, Excel, Dynamics 365 and PowerPoint, while keeping access to frontier models from OpenAI and Anthropic. Maia 200 silicon now supports both OpenAI and MAI models.
In plain terms, Microsoft is building a platform on which OpenAI is the biggest tenant but not the one holding everything up.
What this means for Windows and enterprise IT readers
- Copilot continuity: OpenAI models remain central to Microsoft 365 Copilot and GitHub Copilot. Microsoft's own models are increasingly taking over cost-sensitive tasks, so you may see behavior or model options change over time.
- Procurement leverage: OpenAI models are now available on other clouds. If you're buying Azure OpenAI capacity, you can compare it against alternatives when negotiating.
- Vendor risk reviews: If your AI roadmap depends on Azure capacity, Microsoft's reliance on OpenAI demand is worth a line in your risk register. Capacity allocation, pricing and regional availability all depend on how that relationship develops.
- Model governance: Microsoft is pushing a multi-model approach. Test your agents and workflows on more than one model family now, not during an outage.
The bottom line
The 10-K confirms that OpenAI is Microsoft's largest named commercial relationship, worth $24.1 billion in revenue, a $6 billion receivable and about a quarter of the company's equity. The "quarter of Azure" figure is a rough comparison rather than a disclosure. The October 2025 exclusivity terms are gone, replaced by a non-exclusive license and freedom for OpenAI to use multiple clouds. The real exposure is in the backlog, where OpenAI turned 25% growth into 84%.
Microsoft's bet is that it wins either way: as a landlord when OpenAI grows, as a shareholder when OpenAI's valuation rises, and as a platform owner if the model market fragments. The weak point is the stretch between those outcomes, when OpenAI would need to slow its spending sharply before Microsoft's diversification has matured.