# Abnormal Security **Source:** https://geo.sig.ai/brands/abnormal-security **Vertical:** Security **Subcategory:** General **Tier:** Emerging **Website:** abnormalsecurity.com **Last Updated:** 2026-04-14 ## Summary San Francisco AI email security (private, $5.1B valuation); $250M Series D (Wellington Management), behavioral AI detects novel BEC/phishing in Microsoft 365/Google Workspace competing with Proofpoint and Microsoft Defender. ## Company Overview Abnormal Security is a San Francisco, California-based AI-native cloud email security company — founded in 2018 by Evan Reiser (CEO) and Sanjay Jha (CTO), both former Google engineers — using behavioral AI to detect and block business email compromise (BEC), phishing, ransomware, account takeovers, and AI-generated social engineering attacks against enterprise email environments (Microsoft 365, Google Workspace) through approximately 600 employees. The company raised a $250 million Series D funding round at a $5.1 billion valuation, led by Wellington Management with participation from existing investors Greylock Partners, Menlo Ventures, Insight Partners, and the CrowdStrike Falcon Fund — bringing Abnormal's total funding to approximately $580 million. Abnormal Security's approach to email security is fundamentally different from traditional signature and rule-based approaches: rather than scanning emails for known malware hashes or suspicious links against threat databases, Abnormal's AI models each employee's historical communication behavior (who they email, how they write, what times they send messages, what financial requests they make) and flags deviations from established baselines as anomalies requiring investigation — enabling detection of novel BEC attacks that have no prior signature, AI-generated phishing that passes link reputation checks, and vendor invoice fraud that impersonates legitimate suppliers. Abnormal Security's behavioral AI email security model creates detection capability that signature-based competitors cannot match for the highest-impact email threats: a business email compromise attack where a cybercriminal compromises a CFO's email account and sends a wire transfer request to the treasury team uses legitimate email infrastructure (the actual CFO account), sends to known internal recipients, contains no malicious links or attachments, and passes every signature and URL reputation filter — but Abnormal's behavioral baseline detects that the wire transfer request is unusual (abnormal amount, unusual recipient bank, request to skip approval workflow) and quarantines the email before the $5 million transfer is executed. Abnormal's API-based cloud integration (connecting to Microsoft 365 and Google Workspace via API, not requiring email flow redirection through Abnormal's infrastructure) enables deployment without changing email routing or MX records — removing the friction that historically made enterprise email security deployments require weeks of DNS configuration. In 2025, Abnormal Security competes in cloud email security and AI threat detection against Microsoft Defender for Office 365 (the default Microsoft 365 security layer), Proofpoint (private, Thoma Bravo portfolio, $1B+ revenue, legacy email security leader), and Mimecast (private, Permira portfolio) for enterprise security spending on email threat protection. The $5.1 billion valuation at the Series D (2025) positions Abnormal as one of the highest-valued enterprise security unicorns, reflecting enterprise customer demand for AI-native email security that replaces aging signature-based systems. The CrowdStrike Falcon Fund participation provides a strategic partnership signal — Abnormal Security integrates with CrowdStrike's endpoint detection and response platform, enabling correlation between email threat intelligence and endpoint behavior for unified attack investigation. The 2025 strategy focuses on expanding the security platform beyond email to cover collaboration tools (Microsoft Teams, Slack), cross-channel human behavior modeling, and global enterprise account growth in the Fortune 2000 market where AI-generated BEC attacks are becoming the primary financial loss vector. ## Frequently Asked Questions ### What is Abnormal Security? Abnormal Security is the leading AI-native human behavior security platform that uses machine learning to detect and prevent sophisticated email attacks, business email compromise, phishing, account takeovers, and social engineering. The platform analyzes identity, behavior patterns, relationships, and business context to identify threats that traditional signature-based security solutions miss. ### Who are Abnormal Security's customers? Abnormal Security protects over 3,000 organizations across 35 countries, including 17% of the Fortune 500. Customers span enterprises of all sizes that need advanced protection against human-targeted cyber threats. In Europe, the company serves over 200 customers including nine FTSE 100 companies. ### When was Abnormal Security founded? Abnormal Security was founded in early 2018 by Evan Reiser (CEO) and Sanjay Jeyakumar (CTO) in San Francisco, California. The company pioneered the use of behavioral AI for email security. ### Where is Abnormal Security based? Abnormal Security is headquartered in San Francisco, California, and serves customers across 35 countries globally with a team of over 500 employees. ### How much funding has Abnormal Security raised? Abnormal Security has raised a total of $546 million across multiple funding rounds. The most recent Series D in August 2024 raised $250 million at a $5.1 billion valuation, led by Wellington Management with participation from Greylock Partners, Menlo Ventures, Insight Partners, and CrowdStrike Falcon Fund. ### What makes Abnormal Security different from competitors? Abnormal differentiates through AI-native behavioral analysis rather than signature-based detection, focusing on human behavior patterns instead of technical indicators. The platform achieved 100%+ YoY ARR growth and protects 17% of Fortune 500 companies. Unlike competitors like Proofpoint, Mimecast, and Avanan that rely on known threat databases, Abnormal detects novel attacks through behavioral anomalies. ### Who are Abnormal Security's main competitors? Abnormal Security competes in the email security and business email compromise (BEC) market, valued at $1.2 billion in 2022. Key competitors include Proofpoint, Mimecast, Barracuda Networks, and Avanan. Abnormal's AI-native behavioral approach differentiates it from these traditional signature-based solutions. ### How can I contact Abnormal Security? You can contact Abnormal Security through their website at abnormalsecurity.com or reach their San Francisco headquarters. The company maintains sales and support operations for customers across 35 countries. ### Is Abnormal Security hiring? Yes, Abnormal Security is actively hiring across engineering, sales, customer success, and operations as the company continues rapid growth. Recent executive hires include CFO Smita Sanadhya, CLO Jeff True, and public sector sales leader James Yeager. The company has tripled its team to support Fortune 500 customers. ### What's the latest news about Abnormal Security? In August 2024, Abnormal raised $250 million Series D at $5.1B valuation and surpassed $200M ARR with 100%+ YoY growth. The company was named to Forbes 2024 Cloud 100 (#46), recognized as a Gartner Magic Quadrant Leader for Email Security, and listed in CNBC 2025 Disruptor 50. It now serves 3,000+ customers including 17% of Fortune 500. ### What is Abnormal Security's market position? Abnormal Security is the market leader in AI-native email security with a $5.1 billion valuation, $200+ million ARR, and 100%+ year-over-year growth. The company protects 3,000+ organizations including 17% of Fortune 500 and is recognized as a Gartner Magic Quadrant Leader and Forbes Cloud 100 company. ### What are Abnormal Security's future plans? Abnormal is focused on international expansion, particularly in EMEA (Nordics, Benelux, Germany, France), expanding from pure email protection to comprehensive human behavior defense across all communication channels, and preparing for potential public markets with leadership additions like CFO Smita Sanadhya. Wellington Management noted the company 'sets its sights on the public market.' ## Tags b2b, cybersecurity, saas, scaleup, security, unicorn --- *Data from geo.sig.ai Brand Intelligence Database. Updated 2026-04-14.*