Microsoft Routes Copilot Prompts to In-House MAI Models to Cut OpenAI Costs

Microsoft is now routing tens of thousands of weekly AI prompts in Excel and Outlook to its internally developed MAI models, replacing OpenAI and Anthropic to reduce infrastructure costs ahead of expiring discounts. This follows the July 5 merger of enterprise and consumer Copilot apps and the July 2 launch of Microsoft Frontier Company, which deploys 6,000 engineers with clients backed by $2.5 billion. Earlier milestones include the June 16 global rollout of Copilot Cowork, June 25 finance tools in Excel, and partnerships that helped drive an $37 billion AI run-rate and 18% revenue growth.