Microsoft to add Anthropic models to Office Copilot

Microsoft plans to use Anthropic’s AI models in parts of Office 365 Copilot, partly reducing its reliance on OpenAI, The Information reported. The company will blend Anthropic’s Claude with OpenAI across Word, Excel, Outlook, and PowerPoint, aiming to raise quality for advanced tasks. People cited in the report said Claude’s latest models perform better on jobs like automating financial functions in Excel and generating full slide decks from short prompts. 

Microsoft expects to announce the change in the coming weeks while keeping Copilot pricing at $30 per user per month. OpenAI models will continue to power other Copilot features, and Microsoft says OpenAI remains its partner on frontier models. The move follows months of tense talks around OpenAI’s plan to change its for-profit structure, but product leaders were also swayed by results showing Claude Sonnet 4 outperformed OpenAI in subtle but important ways, like producing more polished slides. 

The Information added that OpenAI’s new GPT-5 is a step up, yet Microsoft will still pay to access Anthropic models via Amazon Web Services because those models are hosted on AWS. Microsoft has not broken out Office Copilot sales, but it says more than 100 million customers use a Copilot product, and analysts estimate Office Copilot is pacing above $1 billion in annual revenue. Internally, executive Charles Lamanna is leading the Office integration. 

The shift fits a wider multi-model strategy: Anthropic already supports advanced agent features in GitHub Copilot, and Microsoft is exploring alternative models for consumer Copilot as well. Anthropic, for its part, recently added native file creation for spreadsheets and slide decks, pitching Claude as moving from adviser to active collaborator. Microsoft continues to expand AI infrastructure, with a data center footprint of more than 400 sites across 70 regions. 

Both Anthropic and OpenAI are also building workplace apps that compete more directly with Microsoft’s suite, and third parties are using Anthropic to automate spreadsheets. Some customers have hesitated to pay more for Office AI after early bugs in PowerPoint deck generation and Excel editing; Microsoft is betting Anthropic can help close that gap.