Microsoft said that it is adding Anthropic's models into its AI assistant Copilot, signalling the days of priority treatment to OpenAI are over as the Sam Altman-led startup also stitches partnerships with other companies.

OpenAI will continue to remain as the default model for new agents in Copilot Studio, said Microsoft in a blogpost.

However, users will have the flexibility to choose from Anthropic models, Claude Sonnet 4 and Claude Opus 4.1, it added.

While Microsoft is the largest investor in OpenAI, cracks have appeared in their partnership.

Just earlier this week OpenAI and Nvidia announced a strategic deal that will see the chip giant investing up to $100 billion in the AI startup. 

OpenAI and Microsoft have also already initiated a deal to restructure the AI startup.

Earlier this month, OpenAI said that it has signed a non-binding agreement with Microsoft, paving the way for the AI startup to restructure into a for-profit company.

OpenAI started as a non-profit organization and is controlled by a nonprofit board. Microsoft invested in OpenAI in 2019 but as OpenAI grew at a fast clip and products between the two companies competed with each other there has been friction between them.

Just earlier this month, OpenAI said it is building its AI-powered hiring platform called OpenAI Jobs Platform, which will directly take on Microsoft's LinkedIn.