The facts
Sierra at a glance.
Read Oct 20, 2026. Valuations and amounts are copied as each source states them; a figure that is only reported (talks, or people familiar with the deal) is labeled as reported.
- Kind of company
- Agents and consumer AIAI agents that do tasks for people and businesses, and new consumer AI products.
- Based in
- United States
- Founded
- 2023Analytics India Magazine, Dec 24, 2025
- Last closed-round valuation
- $4.5B$4.5 billion (Analytics India Magazine, Dec 24, 2025)
- What it has shipped
- Has a product
Founders
- Bret Taylor: "former Salesforce executive"; chairs OpenAI (Analytics India Magazine, Dec 24, 2025)
- Clay Bavor: ex-Google leader who managed Gmail and Google Drive (Analytics India Magazine, Dec 24, 2025)
Sierra introduced the Personal Agent Protocol, an open standard it says it is developing with Meta and industry partners; it later published a draft with 35 design partners (2026-10-09). Oct 6, 2026
Sierra (company-reported), Oct 6, 2026
What it has built
Shipped, or not yet.
“Has a product” is what our search found: something the public can use or buy, a model or API, research only, or nothing public.
Ghostwriter, an agent that builds and optimizes other agents
SourceHorizon agents for multi-day outbound and inbound work, priced on outcomes
SourceDraft Personal Agent Protocol, an open standard developed with Meta and partners
Source1 round
Funding, as reported.
Every round we found, with the amount, valuation and investors as the source states them.
| When | Round | Amount | Valuation | Investors named | Source |
|---|---|---|---|---|---|
| Not stated | not named | $175 million (total $285 million) | $4.5 billion | Greenoaks Capital Partners (lead), Thrive Capital, Iconiq Capital | Analytics India Magazine |
Outside checks
What others have found.
- Sierra says it achieved AIUC-1 certification after an independent audit by Schellman and testing by AIUC (company-reported; we did not fetch the certifier's own page) (Sierra (company-reported), Sep 17, 2026)
Our note: Sierra sells AI customer-service agents to businesses; it is here as an agents company, not a consumer app. Its "over $150M in ARR" (2026-02-06, https://sierra.ai/blog/year-two-in-review) is company-reported. Its 2026 funding could not be verified from a trusted source. The AIM page's metadata is inconsistent (published 2025-12-24, modified 2024-10-29), and the round it describes appears to be from 2024.
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