Sierra secures $950M as competition for enterprise AI intensifies

Sierra, the artificial intelligence startup led by Bret Taylor, is raising a $950 million funding round led by Tiger Global and GV, the company announced Monday, pushing its post-money valuation above $15 billion. The raise gives Sierra more than $1 billion to work with — capital, the company says it will use to become the “global standard” for AI-powered customer experiences.

Like many AI companies, Sierra has been highly proactive in highlighting its growth within an increasingly competitive market. The company says it began with just four design partners a few years ago. Today, it claims to count more than 40% of the Fortune 50 among its customers. It says the agents operating on its platform handle billions of interactions, ranging from mortgage refinancing to processing insurance claims, managing product returns, and supporting nonprofit fundraising campaigns.

The funding announcement follows a period of rapid revenue expansion reported by Sierra. The company previously stated it reached $100 million in annual recurring revenue in late November, and later shared another update in early February indicating it had climbed to $150 million in ARR.

This pace reflects both the urgency enterprises feel in adopting AI and the associated costs of doing so. Taylor, who also serves as chairman of OpenAI and previously held the role of co-CEO at Salesforce, has noted that while agentic AI can ultimately reduce costs and increase revenue for businesses, the initial ramp-up phase can be expensive before those benefits are realised

That dynamic surfaced in a conversation involving Uber CTO Praveen Neppalli Naga, who explained that Uber “blew through our [AI] budget” shortly after adopting agentic AI tools late last year. However, he also pointed out that the company is beginning to see tangible results.

Across a workforce of approximately 8,000 engineers and technical staff, around 10% of all code being produced is now generated autonomously, he said, noting that “10% at our scale is huge.” As a proof of concept, Uber assigned a team to build a new hotel-booking integration entirely using agentic workflows, completing a project that would typically take a year in just six months.

Sierra is also expanding its platform beyond customer-facing agents. In April, the company introduced Ghostwriter, an “agent as a service” tool designed to create additional AI agents. Users can describe their requirements in natural language, and Ghostwriter will autonomously build and deploy a specialised agent to perform those tasks.

For Taylor, this tool reflects a broader vision he outlined at the HumanX conference in San Francisco last month. He argued that many enterprise software tools are underutilised — employees may log in to systems like Workday only during onboarding or open enrollment periods. The future Sierra and its investors envision is one in which users no longer need to navigate complex systems, as AI agents handle those interactions seamlessly.