For a long time, the arrangement was clear: Microsoft relies on OpenAI. Billions invested, an exclusive partnership, ChatGPT technology deeply embedded in every product. Word, Teams, Windows Copilot — all running on OpenAI models under the hood. That's changing.
At the Build conference on June 2, 2026, Microsoft unveiled seven in-house AI models. The flagship is called MAI-Thinking-1 — and it's not a repackaged OpenAI product. It was trained by Microsoft from the ground up.
What Is MAI-Thinking-1?
MAI stands for Microsoft AI. The model specializes in "reasoning" (drawing conclusions across multiple thinking steps). Math, coding, analyzing long documents. Exactly where simpler models tend to get stuck.
Technically, it's a 35-billion-parameter model with a "Mixture of Experts" architecture (MoE — a design where different specialist parts of the model collaborate depending on the task). Sounds complex, but it boils down to: it runs more efficiently and cheaply than one giant model.
Microsoft claims MAI-Thinking-1 beats Anthropic's Claude Sonnet in independent tests and matches Claude Opus on programming benchmarks. Strong claims — benchmarks (comparison measurements between models) don't lie outright, but they do have a talent for selecting convenient truths. Independent verification will follow.
Why Is Microsoft Doing This?
Licensing OpenAI models is expensive. Very expensive. Microsoft pays per API call (every time a product queries the language model), and with hundreds of millions of Office and Windows users, those costs add up to astronomical figures fast.
There's also the strategic picture: OpenAI now sells its services directly to end customers — the same people Microsoft wants to reach with Copilot. That's no longer just a partner; it's also a competitor. Long-term, it would be risky for Microsoft to make its core business dependent on someone playing the same market.
In short: Microsoft wants to hold the steering wheel itself.
What Changes for You?
Short-term, not much — MAI-Thinking-1 is currently only available as a private preview for developers through Azure. No button you can click today, no new subscription.
Medium and long-term, though, the implications are real: AI features in Microsoft 365 (Word, Excel, Outlook, Teams), Windows Copilot, and Bing could gradually switch to these in-house models. As a user, that means the model behind your Copilot will eventually change without you noticing. Whether that makes it better or worse remains to be seen.
More Competition Is Good — for Everyone
Microsoft building its own AI models isn't bad news. Until recently, the market was fairly contained — OpenAI at the front, Google behind it, Anthropic as the quality alternative. Now Microsoft joins with its own model, Meta releases open versions, smaller players are catching up.
More competition typically means: better models, lower prices, less dependence on a single provider. That's good for everyone — not just developers.
The Bottom Line
MAI-Thinking-1 isn't a product you'll download tomorrow. It's a signal: Microsoft has decided it no longer wants to just consume AI — it wants to shape it. For everyday users, not much changes visibly just yet. But the tracks are being laid now.
If you work with Microsoft products daily (and in Germany, sadly, still quite a lot of us do), you'll eventually feel the effects. Better to be informed — than to be surprised.