Sierra, a US-based startup that develops custom AI agents for enterprise customer service, is close to raising US$350 million at a US$10 billion valuation, according to a source cited by Axios.

The funding round is expected to be led by Greenoaks Capital, which also led Sierra’s previous US$175 million round in October 2024 at a US$4.5 billion valuation.

Sierra was founded in 2023 by Bret Taylor, former Salesforce co-CEO and current OpenAI chair, and Clay Bavor, a former Google executive.

The company is reportedly on track to surpass US$100 million in annual recurring revenue and serves hundreds of enterprise customers.

15% of Sierra’s customers have revenue over US$10 billion in June, and half have revenue over US$1 billion.

🔗 Source: Axios

🧠 Food for thought

1️⃣ Sierra’s valuation reflects premium pricing for proven AI customer service solutions

Sierra’s $10 billion valuation at roughly 100x revenue significantly exceeds typical AI company multiples, which averaged 29.7x revenue in 2025 according to industry analysis2.

This premium suggests investors are betting heavily on Sierra’s ability to capture the massive market opportunity in AI-powered customer service, where conversational AI is projected to cut contact center costs by $80 billion by 20263.

The company’s customer base provides strong validation for this premium. With 15% of clients generating over $10 billion in annual revenue, Sierra has proven its solution works for the largest enterprises that demand sophisticated AI capabilities1.

The valuation jump from $4.5 billion to $10 billion in less than a year, while revenue grew past $100 million ARR, demonstrates how quickly proven AI customer service solutions can scale once they achieve product-market fit with enterprise clients1.

2️⃣ Specialized AI agents represent the next evolution in decades-long customer service automation

Sierra’s approach reflects the progression of customer service technology that began with basic Automatic Call Distributors in the 1950s and advanced through predictive dialers in the 1980s to today’s intelligent AI agents4.

Unlike earlier chatbots that frustrated customers with limited capabilities, modern AI agents like Sierra’s can handle complex, contextual conversations while seamlessly escalating to human agents when needed5.

The market timing appears optimal, as 65% of businesses plan to expand AI use in customer support, driven by AI’s ability to handle repetitive tasks while allowing human agents to focus on complex engagements3.