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Abnormal Security — Startup ProfileAI email security — behavior-based protection for business email compromiseHQ: San Francisco, CA, United States | Founded: 2018 | Employees: 600–900 (est. 2026) | Stage: Series D ($5.1B valuation, Aug 2024) | Website: https://www.abnormal.aiAboutAbnormal Security (rebranded Abnormal AI) was founded in 2018 in San Francisco by Evan Reiser (CEO) and Sanjay Jeyakumar (CTO) — the engineers who built behavioral detection at Agari and Twitter's ad/ranking ML. Its platform sits via API over Microsoft 365 and Google Workspace, ingesting email stream + identity + tenant context to model normal behavior per human/vendor and block BEC, account takeover, vendor fraud and AI-generated phishing that secure email gateways (Proofpoint/Mimecast) miss. After early funding, it hit $4B valuation in May 2022 on $210M+ Series C led by Insight Partners (Menlo/Menlo Ventures co-led framing) just 4 years after founding, then $5.1B in Aug 2024 on $250M Series D led by Wellington Management (CNBC/Crunchbase), with $557M total (Tracxn). The company crossed $Key Metrics

Valuation: $5.1B (Aug 2024)

Series D: $250M (Wellington)

Prior Valuation: $4B (May 2022, Insight)

Total Funding: $557M

Founded: 2018

ARR: $100M+ (2023-24 est.)

Funding Rounds

Round: $24M (est.) (2019-11) — Greylock Partners

Round: $50M (est.) (2020-11) — Menlo Ventures

Round: $210M+ ($200M+ reported) (2022-05-10) — Insight Partners

Round: $250M (2024-08-06) — Wellington Management

Key People

Evan Reiser

Sanjay Jeyakumar

Key Competitors

Proofpoint / Mimecast —

Material Security / Armorblox —

Microsoft Defender for Office 365 —

Darktrace / CrowdStrike (email module) —

Timeline Highlights

2024-08-06: $250M Series D at $5.1B (Wellington)

2022-05-10: $210M+ Series C at $4B (Insight)

2019-11: Seed led by Greylock

2018: Founded in SF