TLDR: Sublime Security, a leader in agentic email security, has successfully raised $150 million in Series C funding. This significant investment, led by Georgian, will fuel the acceleration of its AI capabilities to combat the rising tide of sophisticated, AI-driven email attacks. The company’s innovative approach, utilizing specialized AI agents for real-time threat detection and response, has already driven 100% growth in annual recurring revenue in the first half of 2025.
WASHINGTON – October 28, 2025 – Sublime Security, the pioneering platform in agentic email security, today announced it has closed a $150 million Series C funding round. The investment, spearheaded by Georgian, aims to significantly bolster Sublime’s agentic AI capabilities, ushering in a new era of proactive and automated defenses against email-borne threats. This funding round also saw participation from new investors Avenir and 01A, alongside existing investors Index Ventures, IVP, Citi Ventures, and Slow Ventures.
The capital injection arrives at a crucial juncture, as the landscape of email-based attacks, including phishing, continues to evolve rapidly in speed, scale, and sophistication, largely propelled by advancements in generative AI. Sublime Security distinguishes itself from traditional, rigid security vendors by deploying a novel strategy: a dynamic team of specialized AI agents. These agents are designed to protect, triage, and adapt defenses in real-time, thereby empowering security teams to concentrate on their organization’s unique requirements and substantially reduce the resources typically needed to secure their email environments.
This Series C funding follows a period of remarkable expansion for Sublime Security. In the past six months, the company introduced two groundbreaking AI agents that automate critical security functions. The Autonomous Security Analyst (ASA) efficiently investigates and triages threats within seconds, liberating security personnel from time-consuming manual reviews. Concurrently, the Autonomous Detection Engineer (ADÉ) deploys new, customized defenses to counter novel threats in mere hours, effectively eliminating the vendor-induced delays that often leave organizations vulnerable. These innovations have been a key driver behind the company’s impressive 100% growth in annual recurring revenue during the first half of 2025.
Josh Kamdjou, CEO and Co-founder of Sublime, commented on the funding, stating, ‘Our adversaries have constraints, like budgets and time, just like defenders do. AI is changing this dynamic, enabling more sophisticated attacks with less effort at scale. We built Sublime to stop this next generation of attacks by giving security teams an autonomous defense that detects, triages, and adapts at adversary speed, with the transparency and control that enhances work instead of creating friction.’
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Russell Moore, Partner at Georgian, expressed confidence in Sublime’s vision, adding, ‘We believe that Sublime’s use of agentic AI to counter adversaries is redefining how organizations defend themselves – with more context, precision, speed, and transparency than has been possible before. We’re proud to partner with Sublime as it builds the next generation of proactive and programmable autonomous defenses.’
