Microsoft has started replacing OpenAI and Anthropic models with its own MAI systems in Excel and Outlook to reduce its AI expenses. This transition involves tens of thousands of prompts now running weekly on Microsoft's internally developed models. The move comes as Microsoft seeks to manage its AI costs, which have been rising due to extensive use of AI tokens across its products, including the Copilot assistant. AI chief Mustafa Suleyman highlighted the financial motivation behind this shift, noting the company's aim to reduce reliance on external AI providers like Anthropic. This strategy is part of a broader cost-cutting initiative at Microsoft, which includes reducing its workforce by 2.1%, affecting 4,800 jobs, with significant cuts in the Xbox division.