ABNORMAL SECURITY

Evan Reiser was VP of Engineering at Twitter, working on ad fraud detection. He realized the same AI behavioral modeling techniques used to catch fake ad clicks could catch fake emails.

Business email compromise is a $50+ billion annual problem — the FBI calls it the most financially damaging cybercrime — yet most email security tools just look for malicious links and attachments. Reiser founded Abnormal in 2018 to apply behavioral AI to the problem.

The company hit $100 million ARR faster than almost any enterprise security startup in history.

Abnormal Security uses AI to stop email attacks that traditional security misses — business email compromise (BEC), social engineering, vendor fraud, and account takeover. Instead of scanning for malware or known phishing links, Abnormal builds a behavioral model of every person in the organization: who they email, what they talk about, how they write, when they work.

When an email deviates from that pattern — like the CEO suddenly asking for a wire transfer at 2 AM from a weird IP — Abnormal flags it. Subscription-based, priced per mailbox per month.

Integrates directly with Microsoft 365 and Google Workspace via API.

Abnormal Inbound Email Security, Abnormal Email Account Takeover Protection, Abnormal Security Posture Management, Abnormal AI Security Mailbox

Land with email, expand into platform. Abnormal started with inbound email security but is building out into email account takeover protection, security posture management, and AI-powered security operations.

They reached $100M ARR in under 4 years and are reportedly approaching $200M+. Last valued at $5.1 billion in a 2024 funding round.

The path to IPO is clear if growth continues.

Competing for budget against Microsoft's built-in email security (Defender for Office 365) and established players like Proofpoint and Mimecast. Many CISOs wonder why they need a third-party email security tool when Microsoft keeps improving its own.

Abnormal has to prove that behavioral AI catches attacks Microsoft misses — and at $50B+ in annual BEC losses, the evidence suggests Microsoft is indeed missing a lot. The other challenge is expanding beyond email into adjacent categories without losing focus.

Greylock Partners, Menlo Ventures, Sapphire Ventures, Insight Partners, CrowdStrike Ventures, Salesforce Ventures, Wellington Management