Microsoft Swaps OpenAI and Anthropic Models for In-House MAI Across Excel, Outlook; MSFT Stock Up 2%

According to Bloomberg, Microsoft began replacing OpenAI and Anthropic artificial intelligence models with its proprietary "MAI" models on Tuesday, deploying the in-house systems to Excel, Outlook, and GitHub Copilot. The internal models are already handling tens of thousands of user requests weekly across the productivity applications.

The shift aims to reduce multi-billion-dollar dependency on external AI vendors and improve profit margins by circumventing licensing and API fees. Microsoft shares rose 2% following the announcement, reflecting investor confidence in the company's cost-cutting infrastructure strategy.