Sierra raises $950 million: Bret Taylor’s AI Agent Startup Now Valued at Over $15 Billion
Sierra, the AI startup co-founded by OpenAI Chairman and former Salesforce co-CEO Bret Taylor, has closed a funding round of $950 million. The round is led by Tiger Global and GV (Google Ventures), bringing the post-money valuation to more than $15 billion. According to the company, Sierra now has over $1 billion in capital available to become the “global standard” for AI-powered customer experiences.
From design partner to 40 percent of the Fortune 50
Sierra is only about two years old. The company started with four design partners and today claims more than 40 percent of Fortune 50 companies as customers. Billions of customer interactions are said to run on its platform — from mortgage refinancing and insurance claims to returns and fundraising campaigns for NGOs.
The revenue growth Sierra communicates itself is equally steep: in late November 2025, the company reported $100 million in annual recurring revenue (ARR); by early February 2026, it had reached $150 million.
Focus on industry use cases
Unlike the first generation of support bots, which were limited to order tracking or password resets, Sierra positions itself along the entire customer lifecycle. Named application areas include insurance (first notice of loss, claims processing), mortgage origination, banking, healthcare (revenue cycle management), telecommunications, and retail.
Reference customers cited by Sierra include Nordstrom (voice agent “Nora,” launched in five weeks), Asian telco Singtel (live after ten weeks, with a resolution rate of over 70 percent), and US health insurer Cigna, which went into production after eight weeks and, according to Sierra, reduced patient authentication time by 80 percent.
“Ghostwriter”: agents that build agents
In April, Sierra introduced Ghostwriter, a kind of “agent-as-a-service”: users describe in natural language what they need, and Ghostwriter autonomously creates and deploys a specialized agent. The move fits a thesis Taylor recently outlined at the HumanX conference in San Francisco: many enterprise tools, he argued, are barely used — the future lies in systems that end users no longer have to navigate themselves.
A heating market
The round comes at a time when companies are investing heavily in agentic AI — and accepting high ramp-up costs in the process. Uber CTO Praveen Neppalli Naga admitted at TechCrunch’s StrictlyVC event last week that his company “blew through” its AI budget shortly after opening up to agentic tools. Today, roughly 10 percent of the code at Uber is generated autonomously; a pilot project for a hotel booking integration was completed in six months instead of twelve.
