Sierra AI is a customer service agent platform from co-founders Bret Taylor and Clay Bavor that lets large companies answer support requests with AI agents over chat and voice. Sierra raised a $950 million Series E at a $15.8 billion post-money valuation on May 4, 2026, according to CNBC. CNBC also reported more than $150 million in annual recurring revenue within eight quarters.
| Fact | Detail | Source |
|---|
| Founded | 2023 | DefiLlama funding records |
| Co-founders | Bret Taylor (CEO) and Clay Bavor | Reuters, Tracxn |
| Headquarters | San Francisco | CNBC |
| Latest round | $950 million Series E, May 4, 2026 | CNBC |
| Post-money valuation | $15.8 billion | CNBC |
| Lead investors | Tiger Global and GV | CNBC |
| Other investors | Benchmark, Sequoia, Greenoaks | CNBC |
| Annual recurring revenue | More than $150 million within eight quarters | CNBC |
| Named early customers | SiriusXM, WeightWatchers | Reuters, October 2024 |
What does Sierra AI do?
Sierra AI sells AI agents that resolve customer service requests for large companies over chat and voice. A company deploys a Sierra agent in place of, or alongside, its human support staff. Taylor told CNBC that Sierra runs several AI models together and adds its own fine-tuned layers on top of them.
Reuters reported in October 2024 that Sierra aims to reduce hallucinations, which are answers an AI model invents. A wrong answer about a refund or a contract term costs the company money.
Who founded Sierra AI?
Bret Taylor and Clay Bavor founded Sierra AI, and Taylor serves as chief executive. Taylor chairs the OpenAI board, is a former co-CEO of Salesforce and is credited with co-creating Google Maps, according to Reuters. Reuters describes Bavor as a longtime Google executive.
How much is Sierra AI worth?
Sierra AI is valued at $15.8 billion, a mark set by the $950 million Series E that Tiger Global and GV led on May 4, 2026. CNBC reported that the valuation rose from $10 billion in fall 2025, a 58% increase by EPR's calculation from those two figures.
| Date | Valuation | Round detail | Source |
|---|
| Early 2024 | Nearly $1 billion | $110 million from Sequoia and Benchmark | Reuters |
| October 2024 | $4.5 billion | $175 million led by Greenoaks Capital | Reuters |
| Fall 2025 | $10 billion | Prior valuation cited in CNBC's May 2026 report | CNBC |
| May 2026 | $15.8 billion | $950 million Series E led by Tiger Global and GV | CNBC |
Which companies use Sierra AI?
SiriusXM and WeightWatchers were among Sierra's first named customers, according to Reuters in October 2024. Sierra says it now serves more than 40% of the Fortune 50, as Trending Topics reported in May 2026. That figure is a company claim that EPR has not verified.
How does Sierra AI compare with Decagon?
Sierra AI is valued at $15.8 billion (CNBC, May 2026) and Decagon at $4.5 billion (Bloomberg, January 2026), and both companies were founded in 2023. The table sets the two side by side. The AI agents guide comparison covers both companies together.
| Dimension | Sierra AI | Decagon |
|---|
| Latest round | $950 million Series E, May 2026 | $250 million Series D, January 2026 |
| Valuation | $15.8 billion | $4.5 billion |
| Lead investors | Tiger Global and GV | Coatue Management and Index Ventures |
| Named customers | SiriusXM, WeightWatchers | Avis Budget Group |
| EPR rating | 9.0 out of 10 | 8.7 out of 10 |
The EPR AI agents guide ranks Sierra first among customer service agents. The ranking rests on the valuation, the revenue figure and the named enterprise customers above.
How is Sierra AI priced?
Sierra AI uses outcome-based pricing, which means a customer pays when an agent resolves a conversation instead of paying per seat. Sierra does not publish its rates. ValueAdd VC reported in October 2026 that third-party estimates of the per-resolution price range from $1 to $2.50 and that Sierra has not confirmed any of them.
What should buyers check before choosing Sierra AI?
Run Sierra on a sample of your own support tickets and measure the resolution rate before you sign. Outcome-based pricing ties your bill to the number of conversations Sierra counts as resolved, so the contract's definition of resolved sets the cost. Get that definition, and the handling of conversations that escalate to a human agent, in writing.
What else do buyers ask about Sierra AI?
What is Sierra AI?
Sierra AI is a platform that deploys AI customer service agents for large companies over chat and voice. Bret Taylor and Clay Bavor founded it in 2023.
Who founded Sierra AI?
Bret Taylor and Clay Bavor founded Sierra AI. Taylor is the chief executive, chairs the OpenAI board and is a former Salesforce co-CEO, according to Reuters.
What is Sierra AI's valuation?
Sierra AI's valuation is $15.8 billion post-money, set by a $950 million Series E on May 4, 2026, according to CNBC. The prior mark was $10 billion in fall 2025.
Which companies use Sierra AI?
SiriusXM and WeightWatchers were early named Sierra AI customers, according to Reuters. Sierra says it serves more than 40% of the Fortune 50, a claim EPR has not verified.
How is Sierra AI priced?
Sierra AI charges on outcomes, meaning a customer pays when an agent resolves a conversation. Sierra does not publish its rates.
How does Sierra AI compare with Decagon?
Sierra AI is valued at $15.8 billion and Decagon at $4.5 billion. Sierra's latest round was a $950 million Series E in May 2026, and Decagon's was a $250 million Series D in January 2026.
Updated October 7, 2026. Valuation, revenue and funding figures come from CNBC (May 4, 2026), Reuters (October 2024) and Bloomberg (January 2026).
