Microsoft Copilot adds xAI's Grok as a selectable model, rolling out to Word, Excel, and PowerPoint.

Microsoft Copilot adds xAI's Grok as a selectable model, rolling out to Word, Excel, and PowerPoint.

Microsoft has begun rolling out Grok, the model family from xAI (now operating as SpaceXAI after its July merger into SpaceX), as a selectable option inside Microsoft 365 Copilot for Word, Excel, and PowerPoint. The rollout started September 12, 2026 through the Microsoft Frontier Program, is limited to eligible Frontier customers, requires an administrator to enable it (disabled by default), and is not yet available in the EU, EFTA, or UK. Microsoft's post lists SpaceXAI as a new subprocessor in its services and says availability will expand based on feedback from the preview.

Microsoft has anchored its Copilot stack to OpenAI's models for years, so opening a document-editing surface used across its enterprise base to an outside frontier lab is a real crack in that exclusivity, even though it is currently gated behind an opt-in, region-limited preview rather than a default swap. The move also lands weeks after xAI shipped Grok 4.6 claiming parity with GPT-5.6, giving Microsoft's enterprise customers an alternative to test inside tools they already use daily rather than through a separate Grok subscription or API integration.

For enterprise buyers, near-term impact is limited: an admin must turn this on, and EU/UK customers are excluded for now. For xAI/SpaceXAI, the more durable outcome is distribution — reaching Word, Excel, and PowerPoint users without building its own productivity suite is a cheaper path to enterprise seats than a standalone product push, and the subprocessor listing suggests Microsoft is treating this as more than a one-off pilot.

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