Microsoft Brings GPT-5.5 Instant to Microsoft 365 Copilot
Microsoft has added OpenAI’s GPT-5.5 Instant model to Microsoft 365 Copilot and Copilot Studio, just two days after the model became the default option for ChatGPT users. As a result, enterprise customers will gain faster access to OpenAI’s latest AI improvements.
CEO Satya Nadella confirmed the rollout in a LinkedIn post, writing, “Great to bring GPT 5.5 Instant to M365 Copilot today. With quicker, clearer, and more accurate responses, you can get to useful answers with less back and forth.”
The update replaces GPT-5.3 Instant, which had powered Microsoft 365 Copilot since March 2026. Consequently, users can now benefit from improved accuracy and stronger contextual understanding.
Improved Accuracy and Smarter Context Handling
According to OpenAI, GPT-5.5 Instant reduces hallucinated claims by 52.5% on high-stakes prompts involving medicine, law, and finance. Additionally, the model lowers inaccurate responses by 37.3% in conversations that users had previously flagged for errors.
The upgraded model also handles context more effectively. For example, it can reference previous conversations and attached files to deliver more relevant responses. Furthermore, its smart-switching capability allows the system to trigger deeper reasoning when users submit more complex prompts.
These enhancements aim to reduce repetitive back-and-forth interactions. Therefore, enterprise teams may reach useful answers faster while maintaining better reliability across workflows.
Microsoft Expands Its Enterprise AI Push
This rollout follows Microsoft’s earlier integration of GPT-5.5’s full reasoning model across its Copilot ecosystem in late April. That update improved multi-step task execution across GitHub, Microsoft 365, and Azure Foundry.
Users can either manually select a preferred model or allow the system’s auto mode to choose the most suitable option for each request. Meanwhile, OpenAI introduced GPT-5.5 Instant as ChatGPT’s default model on May 5, while GPT-5.3 Instant remains available to paid users for a limited transition period.
The rapid deployment highlights the close collaboration between Microsoft and OpenAI. At the same time, it reflects the growing competition in both consumer and enterprise AI markets.
