Microsoft and OpenAI have had something of a symbiotic relationship, with the former giving billions of capital to a startup AI lab and in return gaining early access to cutting-edge models that are now baked into Microsoft’s suite of productivity software.

The effort is said to focus on the tech giant’s Microsoft 365 Copilot product. It’s an artificial intelligence assistant that ships with the eponymous productivity suite. Microsoft is reportedly working to integrate custom and open-source artificial intelligence models into the assistant, which is currently powered by technology from OpenAI.

Microsoft has been working on adding internal and third-party artificial intelligence models to power its flagship AI product Microsoft 365 Copilot, in a bid to diversify from the current underlying technology from OpenAI and reduce costs, sources familiar with the effort told Reuters.

"Microsoft is diversifying its AI strategy for Microsoft 365 Copilot by integrating internal and third-party AI models, including its latest Phi-4 model.