Sierra Raises $950 Million to Scale AI Customer Experience Platform to $15 Billion Valuation

New updates have been reported about Sierra.

Sierra, the AI startup founded by Bret Taylor, has secured a $950 million funding round led by Tiger Global and GV, lifting its post-money valuation above $15 billion and giving the company over $1 billion in total capital to deploy. Management plans to use the funding to entrench Sierra as the default infrastructure for AI-driven customer experiences, positioning its platform as a core system for large enterprises rather than a point solution.

Sierra reports rapid commercial traction, claiming it has grown from four design partners a few years ago to serving more than 40% of the Fortune 50, with its AI agents now managing billions of customer interactions across tasks such as mortgage refinancing, insurance claims, product returns, and nonprofit fundraising. The company’s revenue ramp has been equally sharp, with annual recurring revenue rising from $100 million in late November to $150 million by early February, highlighting strong enterprise demand for agentic AI despite significant upfront deployment costs. Beyond customer-facing use cases, Sierra is expanding into internal automation with Ghostwriter, an “agent as a service” launched in April that lets users describe a need in natural language and then automatically builds and deploys a specialized AI agent, reflecting Sierra’s broader thesis that future enterprise software will be accessed through agents rather than complex user interfaces.