OpenAI and Microsoft: what the partnership is, and where you meet it
Three separate things link the two companies, and knowing which is which explains why the same model answers differently in ChatGPT and in Copilot.
Published by AI Knows Us · Updated 12 October 2026
Microsoft is OpenAI's largest commercial partner and holds a minority equity stake in it. It does not own OpenAI. The link has three separate parts, and people conflate them constantly. First, investment: Microsoft has put money in and holds a stake, while control sits with OpenAI's own non profit governance structure. Second, cloud: OpenAI's models are trained and served at enormous scale on Microsoft Azure, and Microsoft resells them to businesses as the Azure OpenAI Service. Third, distribution: Microsoft ships OpenAI models inside its own products under the Copilot name, in Windows, Microsoft 365, GitHub and Bing. OpenAI separately sells ChatGPT and its own API direct to consumers and companies, which is why the two firms are partners and competitors at the same time.
If you came here to work out which of the two to buy from, that third part is the one that matters, and the short answer is that you are choosing a product and a contract rather than a model.
The three parts, kept apart
- Ownership and governance. OpenAI began as a non profit and now runs a public benefit corporation under non profit oversight. Microsoft is an investor with a minority holding and commercial rights. Headlines that say Microsoft owns OpenAI are describing an investment as if it were an acquisition.
- Infrastructure. Azure is the platform the models run on, and that compute relationship is the heaviest part of the deal in practice. OpenAI has also added further compute suppliers, so Azure is central rather than sole.
- Product rights. Microsoft can put OpenAI models into its own software and sell access to them through Azure. This is why an enterprise can buy the same family of models from either company, under very different paperwork.
Where you actually meet OpenAI models inside Microsoft
| Product | What it does | Who it is for |
|---|---|---|
| Microsoft Copilot | The consumer and web assistant, with web answers and image generation | Anybody, free tier available |
| Microsoft 365 Copilot | Assistance inside Word, Excel, PowerPoint, Outlook and Teams, grounded in your own organisation's files and mail | Licensed business users |
| GitHub Copilot | Code completion, chat and agent work inside the editor and on pull requests | Developers |
| Copilot in Bing and Edge | Conversational answers alongside search results, with links | Searchers |
| Azure OpenAI Service | The models as an API under an Azure contract, with Azure's regions, identity and compliance controls | Engineering and IT teams |
| Copilot Studio | Building your own assistants over company data and connectors | Internal developers and IT |
Microsoft has also begun using models from other suppliers, including its own in house models, in parts of the Copilot range. So Copilot is a product name, not a promise about which model answered you.
Why the same question gets different answers in ChatGPT and Copilot
Three reasons, and none of them is the model being secretly worse in one place.
- Different retrieval. A Microsoft surface typically searches with Bing. ChatGPT's search does its own retrieval. Different sources arrive, so different companies get named.
- Different grounding. Microsoft 365 Copilot can read your tenant: your documents, mail and chats. ChatGPT reads what you give it, plus whatever connectors you turn on.
- Different system instructions. Each product wraps the model in its own rules about tone, length, citation and safety, and those rules change the output as much as the model does.
Buying from Microsoft or buying from OpenAI
- Choose Azure OpenAI when you already have an Azure agreement, when procurement wants one vendor and one invoice, when you need regional data residency and Microsoft's compliance paperwork, or when the work sits next to Azure identity, networking and storage.
- Choose OpenAI direct when you want the newest models and features as soon as they ship, when you are building on the assistant and agent tooling OpenAI releases first, or when you are a small team that wants to start this afternoon.
- Either way, write portability in. Keep prompts, evaluation sets and retrieval logic in your own code so the provider is a configuration value.
Why any of this matters outside IT
Because the two companies between them sit on most of the places a buyer now asks a question. Somebody researching a supplier might ask ChatGPT on their phone, Copilot in the Windows taskbar, Copilot in a Teams chat, or type the question into Bing. Those surfaces draw on different retrieval, so the set of companies named is different in each. A business that is well described on the pages Bing indexes can be named in Copilot and absent from an assistant that retrieves elsewhere, and the reverse happens just as often.
This page covers the relationship between the two companies and the products it produces. For how a question is actually answered inside an assistant, how search engines work and how assistants choose which brands to name cover that ground.
Asked and answered: OpenAI and Microsoft
Does Microsoft own OpenAI?
No. Microsoft is an investor with a minority stake and broad commercial rights. OpenAI's control structure sits with its own non profit oversight, not with Microsoft.
Is Copilot the same as ChatGPT?
They are different products that have used the same underlying model families. Copilot is Microsoft's assistant, wrapped in Microsoft's retrieval, data access and rules. ChatGPT is OpenAI's own product. Answers differ accordingly.
Is Azure OpenAI the same as the OpenAI API?
Close, deliberately. Model names and request shapes line up closely so code moves across with small changes, while deployment, authentication, regions and billing follow Azure's model. New releases usually appear at OpenAI first.
Do Microsoft and OpenAI compete?
Yes, in products. Microsoft 365 Copilot and ChatGPT's business plans sell to the same buyer, and both companies court the same developers. The partnership and the competition run in parallel, which is normal at this scale.
Which one should a small company use?
If your work lives in Microsoft 365, the Copilot licences sit where your documents already are. If you are building something, start with OpenAI direct and keep the interface swappable.
The question worth asking in both
Since Copilot and ChatGPT retrieve from different places, the set of companies each one recommends in your category is different, and so is the set of pages each one quotes. Gemini, Perplexity, Claude and Google's AI Overviews add four more answers to the same question.
Run the test rather than assuming. Take the question a customer would actually type, leave your own company name out of it so nothing is primed, ask it in two or three of these assistants, and write down who gets named and what gets cited. The pattern in those citations is usually the first clear instruction on what to fix. AI Knows Us measures those answers across the main assistants and shows which sources they are built from.