Microsoft is ending OpenAI’s exclusive role in powering Office 365’s generative AI features. According to The Information, the company will soon integrate Anthropic’s Claude Sonnet 4 model into Word, Excel, PowerPoint, and Outlook.

The decision follows internal testing, which showed Anthropic’s model outperforming OpenAI’s technology in specific productivity tasks, especially design-heavy and spreadsheet-related work. Sources emphasized that the move is not a negotiating tactic with OpenAI.

Anthropic did not immediately respond to requests for comment.

In a twist reflecting the AI industry’s complex alliances, Microsoft will obtain access to Claude models through Amazon Web Services. Amazon is both a competitor in cloud services and one of Anthropic’s largest investors, committing $4 billion since 2023.

Despite the change, Microsoft confirmed its long-term commitment to OpenAI. “As we’ve said, OpenAI will continue to be our partner on frontier models and we remain committed to our long-term partnership,” a Microsoft spokesperson told Reuters. Microsoft has invested more than $13 billion in OpenAI and is now negotiating terms for continued access to its models as the partnership evolves.

The partnership between Microsoft and OpenAI dates back to 2019 and has so far enabled Microsoft to roll out Copilot assistants across its ecosystem. However, a UK government study recently found no clear productivity boost from Copilot use in workplace settings.

Meanwhile, OpenAI is diversifying as well:

Microsoft is also expanding beyond OpenAI, having introduced DeepSeek models through Azure earlier this year and offering Claude via GitHub Copilot.

For Anthropic, this agreement with Microsoft is a milestone against its more established rival. Founded in 2021 by ex-OpenAI executives, including CEO Dario Amodei, the company markets Claude as a “more steerable” alternative to ChatGPT.

The partnership indirectly extends Amazon’s influence, since Microsoft will rely on AWS infrastructure to deliver Anthropic-powered features within Office 365.

Q: What change is Microsoft making to Office 365?
A: Microsoft will integrate Anthropic’s Claude Sonnet 4 AI into Office 365, ending OpenAI’s exclusivity.

Q: Why is Anthropic being added?
A: Internal testing showed Claude performs better than OpenAI’s models in tasks like visual design and spreadsheet automation.

Q: How will Microsoft access Anthropic’s AI?
A: Through Amazon Web Services (AWS), even though Amazon is a cloud rival and an Anthropic investor.

Q: Does this mean Microsoft is ending its partnership with OpenAI?
A: No. Microsoft confirmed its $13 billion investment and long-term partnership with OpenAI remains intact.

Q: What does this mean for Anthropic?
A: It represents a strategic win, giving Anthropic a place inside Microsoft Office and boosting its competitive position against OpenAI.

Microsoft’s decision to diversify Office 365’s AI sources underscores a broader industry trend: no single AI provider can meet all demand at scale. As OpenAI, Microsoft, and Anthropic each hedge their bets, alliances are becoming increasingly fluid across the sector.

For users, the change could mean more reliable and varied AI-powered features in Office, especially in design and data-heavy workflows.

In the longer term, this move suggests that AI integration in workplace tools will remain a multi-provider ecosystem, giving companies like Anthropic a stronger foothold alongside established giants.

Editor’s Note: This article was created by Alicia Shapiro, CMO of AiNews.com, with writing, image, and idea-generation support from ChatGPT, an AI assistant. However, the final perspective and editorial choices are solely Alicia Shapiroo’s. Special thanks to ChatGPT for assistance with research and editorial support in crafting this article.