Microsoft

Microsoft completes its $19.7 billion acquisition of Nuance Communications, at the time the largest acquisition in Microsoft's history. Nuance was a leader in speech recognition and conversational AI, powering clinical intelligence tools used in over 77% of U.S. hospitals. The deal significantly expanded Microsoft's healthcare AI capabilities, bringing Nuance's Dragon Ambient eXperience (DAX) and cloud-based clinical AI under Microsoft's umbrella.

Microsoft launched Azure OpenAI Service, providing enterprise customers with secure, compliant access to OpenAI's GPT models through Azure's cloud infrastructure. The service became the primary channel for enterprise AI adoption, integrating GPT-4 and other OpenAI models with Azure's security, compliance, and data residency features.

Microsoft announced an additional $10 billion investment in OpenAI over multiple years, at a $29 billion valuation. The deal included integrating OpenAI models across Microsoft products and Azure AI services.

Microsoft launched Bing Chat (later renamed Microsoft Copilot), integrating OpenAI's GPT-4 into Bing search and Edge browser. This marked Microsoft's first major consumer AI product from the OpenAI partnership.

Microsoft announced Microsoft 365 Copilot, integrating AI assistants into Word, Excel, PowerPoint, and Outlook. The enterprise AI subscription was later priced at $30/user/month, demonstrating the monetization of generative AI.

Microsoft launched GitHub Copilot Chat, bringing GPT-4-powered conversational assistance directly into developer workflows, alongside Copilot X with PR descriptions, code reviews, and voice commands. The expansion transformed Copilot from an autocomplete tool into a comprehensive AI development assistant.

Microsoft launched Microsoft 365 Copilot to general availability, embedding GPT-4 across Word, Excel, PowerPoint, Teams, and Outlook. The launch represented the first large-scale deployment of generative AI into productivity software used by hundreds of millions of workers worldwide.

Microsoft Research released the Phi-3 family of small language models, with Phi-3-mini (3.8B parameters) achieving performance comparable to Mixtral 8x7B on benchmarks. The breakthrough in data-efficient training demonstrated that carefully curated training data could dramatically reduce the computational cost of capable models.

Microsoft launched the Windows Copilot Runtime, embedding on-device SLM inference and NPU-accelerated AI features directly into the Windows operating system. The platform enabled local AI processing for real-time video effects, image generation, and document analysis without cloud connectivity.

Microsoft released Phi-4, a 14-billion parameter state-of-the-art small language model (SLM) that excelled at complex reasoning in math and conventional language processing. The model introduced innovative synthetic data generation methods and optimized training curriculum and data mixture. Phi-4 was made available on Azure AI Foundry and HuggingFace, advancing the frontier of what small models could achieve.

Microsoft AI unveiled MAI-1-preview and MAI-Voice-1, the company's first internally developed foundation models, built under Mustafa Suleyman and wired into Copilot. The move marked a decisive strategic shift away from total dependence on OpenAI technology toward proprietary in-house models, setting the stage for the full MAI model family unveiled at Build 2026 and reducing reliance on its OpenAI partnership.

At Build 2026, Microsoft announced seven first-party MAI (Microsoft AI) models spanning five modalities, including MAI-Thinking-1 (flagship reasoning model, 35B active parameters, 1T total), MAI-Code-1-Flash (agentic coding), MAI-Image-2.5, MAI-Transcribe-1.5, and MAI-Voice-2. All models were pre-trained from scratch on commercially licensed data with no distillation from rivals, signaling a major strategic shift to reduce dependence on OpenAI while still offering OpenAI models through Azure.

Microsoft and Mistral AI announced a multibillion-dollar agreement supporting AI infrastructure development in Europe, with Microsoft using part of Mistral's expanded European computing capacity and adding Mistral Medium 3.5 and OCR 4 models to Microsoft Foundry and Copilot Studio.

Microsoft began rolling out xAI's Grok models to Microsoft 365 Copilot across Word, Excel, and PowerPoint, with CEO Satya Nadella announcing the rollout and Elon Musk confirming the same day. Initially a preview for Microsoft Frontier program customers (admin-enabled, excluded from the EU, EFTA, and UK), the rollout made Microsoft the first platform serving OpenAI, Anthropic, xAI, and in-house MAI models in the same productivity suite -- a concrete consummation of its shift from exclusive OpenAI partner to neutral AI aggregator, and the first time a Musk-owned model reached mainstream enterprise Office tools.