Sierra
Sierra is an Enterprise Voice Agents company founded in 2023 and based in San Francisco, United States. It has raised $1.6B in total funding, most recently a Series D in 2026 at a $15.8B valuation.
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.
At a glance
Total raised
$1.6B
Headcount
501-1k
Headquarters
San Francisco
United StatesFounded
2023
Status
Private
Latest valuation
Funding history
Total raised
$1.6B
Rounds tracked
0
Latest stage
Series D
Latest valuation
$15.8B
No dated funding rounds on file. This company is privately held and may be raising or operating on undisclosed capital.
In the news
Sierra · last 30 days
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Leadership
Bret Taylor
Co-Founder & CEO
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