Abnormal Security

Abnormal Security — now operating as Abnormal AI — has built the most successful AI-native email security platform in the market, using behavioral AI to detect and prevent sophisticated social engineering, business email compromise, and account takeover attacks that legacy secure email gateways consistently miss.

Founded in 2018 by CEO Evan Reiser and CTO Sanjay Jeyakumar, the company reached $200M+ ARR in just five years while maintaining 100%+ year-over-year growth. A $250 million Series D in August 2024, led by Wellington Management with participation from Greylock Partners, Menlo Ventures, Insight Partners, and CrowdStrike Falcon Fund, valued the company at $5.1 billion — making it one of the most valuable private cybersecurity companies in the world.

Abnormal's technical differentiation lies in its three-layer behavioral AI framework that analyzes identity, context, and risk to build baselines of normal communication patterns across an organization. Rather than relying on static signatures or rules, the platform detects anomalies in real-time — catching impersonation attempts, credential phishing, and compromised account behavior that evade traditional defenses. The API-based architecture deploys in minutes with no MX record changes, a stark contrast to legacy gateway replacements.

Category leader in AI-native email security. Abnormal's behavioral approach has proven that AI can fundamentally replace the secure email gateway — a market that was considered solved by the legacy incumbents. With $546M total funding and clear IPO trajectory, the company represents the gold standard for AI-first cybersecurity companies.