Using the most advanced AI models at a corporate scale isn’t cheap, even for a company as massive as Microsoft. The cost of AI tokens, the unit used to measure how much computing work a model is doing, is getting so expensive that Microsoft is reportedly turning to its own models to save some cash. Bloomberg reports, citing an unnamed source, that tens of thousands of AI prompts each week in Microsoft’s Excel and Outlook software are now being completed using Microsoft’s own MAI models. The spreadsheet and email programs previously relied more heavily on models from OpenAI and Anthropic to complete some tasks. That is still only a small fraction of Microsoft’s overall AI usage, Bloomberg notes. For example, Copilot, the company’s workplace AI assistant, requires massive amounts of AI tokens.
Microsoft declined to comment on the report. The news comes a little over a month after Microsoft announced seven new in-house models, including MAI-Thinking-1, Microsoft AI’s first reasoning model.
At the time, the company said MAI-Thinking-1 was built for “high efficiency and performance, but importantly, at a low-token cost.” Microsoft describes the model as a mid-sized, 35 billion active-parameter model with a 256K context window. According to a blind test, it matched the coding abilities of Anthropic’s popular Claude Opus 4.6. Microsoft also rolled out new image, transcription, voice, and coding models. The new models arrive as cheaper and more efficient AI models are getting more attention across the industry.
