Email security, long treated as a solved problem, is suddenly back in the spotlight. Sublime Security raised $150 million in Series C funding to expand its adaptive email-threat platform amid a surge in phishing and renewed investor interest in the sector. The global email-security market is expected to more than double from $5.17 billion in 2025 to $10.68 billion by 2032.
The new round, led by Georgian, highlights how attackers are innovating faster than defenses. Sublime’s own research found that 90 percent of malicious emails are now customized for their target, often blending URL-based and multi-vector tactics, according to a Sublime Security Threat Report.
The Washington-based company said the funds will expand its autonomous system that detects, triages, and adapts defenses in real time. CEO Josh Kamdjou said the goal is to give security teams “an autonomous defense that detects, triages, and adapts at adversary speed,” according to a prepared statement.
The investment follows 100 percent growth in recurring revenue during the first half of 2025 and complete retention of enterprise customers including Spotify, Snowflake, and Zscaler. Investor Russell Moore of Georgian called Sublime’s approach “a redefinition of how organizations defend themselves – with more context, precision, speed, and transparency than has been possible before.”
The raise underscores a larger shift toward automated, adaptive defense models across cybersecurity. As phishing grows more targeted and harder to detect, platforms that continuously learn and respond in real time are drawing new attention from both CISOs and venture capital.
