Anthropic pledges $30B in Azure compute as Claude moves into Copilot

Microsoft spent years as the most famous OpenAI backer in tech. Now its flagship AI assistant has a second brain on call, and that brain belongs to Anthropic. Microsoft has been weaving Anthropic’s Claude models into its Copilot ecosystem. Users can now pick Claude for coding help, research and workflow management instead of defaulting to OpenAI. How Claude ended up inside Copilot The rollout started on September 24, 2025. Copilot users gained the option to select Claude variants, including Sonnet 4 and Opus 4.1, next to the existing OpenAI models. Claude models became the default for many commercial customers. Its models remain available inside Copilot, so this is an expansion of the menu, not a replacement of the chef. For most commercial users outside the EU, EFTA and the UK, Claude is switched on by default. Inside those regions, an administrator has to turn it on manually. The reason is regulatory. Claude’s availability in Europe is restricted because of compliance with local data boundary rules. The money behind the partnership The relationship got considerably more expensive on November 18, 2025. That day, Anthropic pledged to secure $30 billion in Azure compute capacity. Mi...