WHAT SHIPPED
● Announced 12 September by Satya Nadella. Musk confirmed the same day.
● Where: Microsoft 365 Copilot across Word, Excel and PowerPoint, plus GitHub Copilot and workplace tools.
● Who: Frontier programme customers. An administrator must enable it.
● Who cannot: the EU, EFTA and the UK are excluded during preview.
The exclusion is the part worth asking about
Microsoft says Grok will not be available to Frontier customers in the European Union, the European Free Trade Association or the United Kingdom during the preview phase.
No reason has been published. There are two obvious candidates and both are speculation: the EU AI Act imposes obligations on general-purpose model deployment that a preview may not yet satisfy, and xAI is facing litigation in California alleging it knowingly commercialised and profited from non-consensual image generation features that reached women and minors — allegations Musk has denied knowledge of.
GEOGRAPHIC CARVE-OUTS ARE USUALLY LEGAL, NOT TECHNICAL
A model that works in Seattle works in Stockholm. When a rollout skips a region, the reason is almost always regulatory exposure or contractual risk rather than engineering.
Which region gets excluded tells you where the company thinks its liability is. That is worth noting even when nobody explains it.
This was not sudden
The announcement reads as a launch. The rollout was incremental and has been running since February.
| Date |
What landed |
| May 2025, Build | xAI models hosted on Azure AI Foundry. The groundwork |
| 19 February 2026 | Grok 4.1 Fast preview in Copilot Studio, US developers |
| 16 June 2026 | PowerPoint add-in |
| 18 June 2026 | Word add-in |
| 20 July 2026 | Excel |
| August 2026 | Grok 4.5 in GitHub Copilot |
| 12 September 2026 | Broad availability in Copilot for Frontier customers |
Copilot has stopped being a product
Microsoft is OpenAI's largest investor and built Copilot on OpenAI models. It now ships Anthropic models inside Copilot as well, and from this week xAI models too.
That makes Copilot a model marketplace rather than a product with a model inside it. An enterprise can point legal at one engine and marketing at another, in the same interface, under one licence.
It is a strong position for Microsoft. It also means no model vendor owns the interface most office workers will actually use, which is a worse outcome for OpenAI than for anyone else in that list.
The alliance map, for context
- Microsoft is OpenAI's largest investor and now distributes its competitors alongside it.
- SpaceX acquired Cursor for $60 billion, and OpenAI models leave Cursor on 12 November.
- Anthropic pays SpaceXAI a reported $1.25 billion a month for Colossus compute, under terms that reportedly let Musk withdraw it.
- Apple is in litigation with OpenAI, with a hearing on 1 October.
Everyone is buying from, suing, or distributing everyone else. The useful read for a buyer is that partnership announcements are not commitments, and a model available inside a product today may not be next quarter — as Cursor users are about to find out.
What it means if you use Office
| If you are... |
What changes |
| A Frontier customer outside Europe | Your admin can enable Grok as a model option. Nothing to install |
| In the EU, EFTA or UK | Not available during preview. No timeline published |
| An IT administrator | This is opt-in. Worth deciding deliberately rather than by default |
| On standard Microsoft 365 Copilot | Nothing yet. Frontier is the early-access programme |
| Choosing models for a team | Ask what data leaves your tenant and under whose terms. Different model, different vendor agreement |
That last row is the one worth raising with your admin. A model selector makes switching feel like changing a font. It is a change of processor, and the data handling terms differ by vendor.
Sources
FAQ
Is Grok available in Microsoft Copilot?
Yes, for Frontier programme customers, announced 12 September 2026. An administrator must enable it, and it is not available in the EU, EFTA or the UK during the preview phase.
Which apps does it cover?
Microsoft 365 Copilot across Word, Excel and PowerPoint, plus GitHub Copilot and workplace tools. Grok 4.5 reached GitHub Copilot in August.
Why is it excluded in Europe?
Microsoft has not published a reason. Geographic carve-outs in a rollout are typically regulatory or contractual rather than technical.
Do I need to install anything?
No. Once an administrator enables it, Grok appears as a model option inside the Copilot interface.
Does Microsoft still use OpenAI models?
Yes. Copilot now offers OpenAI, Anthropic and xAI models in the same interface, which makes it a model marketplace rather than a product built on one vendor.
Should my organisation enable it?
That is an opt-in decision worth making deliberately. Different models mean different vendor agreements, so the question to ask is what data leaves your tenant and under whose terms.