Microsoft said it is expanding model choice in Copilot by adding Grok models from xAI through the Microsoft Frontier Program in Word, Excel and PowerPoint.
The Copilot blog post is dated Sept. 12, 2026, and the page showed an update stamp of Sept. 14, 2026. Microsoft said SpaceXAI has been added to its Online Services Subprocessor List, and access is managed through a dedicated administrative setting that is disabled by default.
Microsoft described the release as a focused Frontier preview to gather feedback on common productivity scenarios. Grok is not available to Frontier customers in the European Union, the European Free Trade Association or the United Kingdom during the preview, the company said.
Independent coverage on Sept. 14, 2026, from Forbes and Office Watch repeated the same admin opt-in, subprocessor listing and regional exclusion. Microsoft Learn documentation says SpaceXAI models are hosted outside Microsoft and that Microsoft customer agreements, data residency commitments and related controls do not apply when an organization chooses those models; xAI enterprise terms apply instead.
What remains open is which Grok version powers the Office preview, since the Copilot blog names the model family without a version string, and how far Microsoft will extend availability beyond Frontier Word, Excel and PowerPoint after it reviews feedback and product fit.
