Microsoft is adding Anthropic’s AI models to Office 365 to complement its long-standing work with OpenAI, using the models in parts of the suite where they outperform alternatives while keeping pricing unchanged and maintaining its existing OpenAI integrations.
The company will pay to license Anthropic’s technology — most likely the Claude Sonnet 4 model — for selected Office features. Internal tests reportedly showed Anthropic’s models produce especially strong results for crafting polished PowerPoint presentations and automating complex Excel tasks, prompting Microsoft to route those workloads to the new supplier when it offers better performance.
Microsoft emphasized that this move supplements rather than replaces its collaboration with OpenAI. Frontier models from OpenAI will continue to power other Office experiences, including Word, Outlook and Copilot features. The two-supplier approach is intended to let Microsoft pick the best model for each task while preserving the benefits of its existing investments.
A notable element of the arrangement is how Microsoft will access Anthropic’s models: through Amazon Web Services. Using AWS is striking because AWS is both a cloud rival and a major investor in Anthropic, underscoring Microsoft’s willingness to prioritize model performance and supplier diversity over keeping all services on its own cloud infrastructure.
Financial details of the deal were not disclosed. Microsoft said customers will not see changes to pricing for AI-enabled Office tools as a result of the integration. The company framed the partnership as a way to improve product capabilities without passing additional costs to users.
Industry analysts see the move as a hedge against overreliance on a single AI provider and a reflection of a broader trend toward multi-model strategies. Enterprises increasingly plan to mix and match models from different vendors to exploit specific strengths, manage risk, and improve resilience.
For users, the change should mean more tailored AI functionality inside Office apps: features will be driven by the model that performs best for the given task, potentially improving quality for tasks like slide design and spreadsheet automation while keeping familiar tools and pricing intact.
