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Sierra — Enterprise Voice Agents · fobi

Live

Coming soon

Agriculture Tech
AI Agents & Models
Autonomy
Avatars & Digital Humans
Biotech / Synthetic Biology
Blockchain / Crypto
Brain-Computer Interfaces
Climate Tech
Cloud & Edge Computing

Commerce
Cybersecurity
Data Infrastructure
Defense
Digital Identity
Education Tech
Energy
Fashion & Textiles
Food Tech

Healthcare Systems
Longevity & Human Enhancement
Manufacturing
Materials Science
Mobility
Quantum Computing
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Sierra

Sierra builds conversational AI agents for enterprise customer-experience workflows, replacing tier-1 support teams. Founded by Bret Taylor (ex-Salesforce co-CEO) and Clay Bavor (ex-Google Labs); customers include ADT, SiriusXM, and OluKai.

Sierra hit $100M ARR in seven quarters and achieved a $15B valuation, the fastest enterprise-AI revenue ramp on record.

sierra.ai Enterprise Voice Agents

United Statesprivate

At a glance

Total raised

$1.6B

last round series d

Headcount

501-1k

approximate · public range

Headquarters

San Francisco

United States

Founded

2023

3 years active

Status

Private

Enterprise Voice Agents

Latest valuation

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Date	Stage	Amount	Valuation	Lead investors
May 4, 2026	Series D	$950M	$15.8B	Tiger Global, GV
Sep 4, 2025	Series C	$350M	$10B

AI bull / bear

Bull case

Sierra achieved $100M ARR in just seven quarters with a $15B valuation, the fastest enterprise-AI revenue ramp on record. That is not hype — that is paid deployments at marquee names like ADT, SiriusXM, and OluKai. Bret Taylor and Clay Bavor bring the exact combination of enterprise distribution DNA and deep tech credibility that this market demands. Sierra replaces tier-1 support teams entirely, not just augments them, meaning each customer win represents a multi-million-dollar annual contract that expands as the agent handles more volume. The voice-agent category is still early; Sierra has first-mover status with a product that actually works at scale. As enterprises finish piloting generic LLMs and seek purpose-built, secure, and reliable voice agents, Sierra sits in the pole position to capture the bulk of what will be a tens-of-billions dollar market for outsourced customer service automation.

Bear case

Sierra's $15B valuation implies a 150x multiple on $100M ARR — an extreme multiple that demands near-perfect execution into a market that is about to get crushed by competition. Every major cloud provider (AWS, GCP, Azure) and every CCaaS incumbent (Salesforce/Service Cloud, Zendesk, Five9) is racing to embed voice agents directly into their platforms, often at zero marginal cost to existing customers. Sierra is a standalone product that must displace entrenched workflows and procurement relationships. Bret Taylor's Salesforce pedigree cuts both ways: enterprises remember the expensive, rigid AI pivots of the past and may treat Sierra as another overhyped tool rather than a core replacement. Voice agent accuracy in high-stakes environments (billing disputes, emergency scenarios) remains fragile. One high-profile failure at ADT or SiriusXM could freeze enterprise adoption across the entire category, and Sierra carries that category risk alone as the highest-profile standalone player.

Generated by deepseek-v4-flash · June 2, 2026Refreshes quarterly · see disclosures

Sierra

At a glance

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Funding history

How they make money

Founder backgrounds

Bret Taylor

Clay Bavor

AI bull / bear

In the news

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Leadership

Products

Sierra AI Agent Platform

Agent Studio 2.0

Ghostwriter

Open roles

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