The latest
Microsoft has started replacing OpenAI and Anthropic models with its own internally built MAI models in products such as Excel and Outlook, Bloomberg reported, citing a person familiar with the work. The move is still limited, but it marks a clear push to lower the cost of running AI features across Microsoft’s workplace software.
Details
• Where it’s happening: Bloomberg said Excel and Outlook are now completing tens of thousands of AI prompts each week using Microsoft’s MAI models.
• Previous setup: The two apps had relied more heavily on models from OpenAI and Anthropic, according to Bloomberg’s source.
• Still early: MAI models account for only a small share of Microsoft’s overall AI usage, but the shift shows the company is making progress with in-house models.
• Cost pressure: Microsoft AI chief Mustafa Suleyman said in June that the company wants to reduce and eventually eliminate the cost of using Anthropic models.
• New models: Microsoft announced 7 AI models at its Build conference, including one it says can match the coding performance of Anthropic’s earlier Opus 4.6 model at lower cost.
Background
Microsoft uses huge volumes of AI tokens in products such as Copilot. Its partnership with OpenAI gives it discounted access for now, but Bloomberg said the company is preparing for a future where relying on outside labs could become much more expensive.
What to watch
The next test is whether Microsoft expands MAI models into GitHub Copilot, Teams transcription and more workplace tools — and whether it can cut costs without weakening the user experience.
