Sublime Security, a leading agentic email security platform, has raised $150m in Series C funding to advance its AI-driven approach to cyber defence.
The round was led by Georgian, with participation from new investors Avenir and 01A, as well as existing backers Index Ventures, IVP, Citi Ventures, and Slow Ventures.
The fresh capital comes amid a surge in email-based cyberattacks, increasingly fuelled by generative AI. Unlike traditional, static security tools, Sublime’s technology deploys a suite of specialised AI agents that continuously protect, triage, and evolve their responses to threats in real time. This dynamic approach allows security teams to focus on strategic priorities rather than manual email review and maintenance.
Founded to modernise email defence, Sublime Security’s platform empowers enterprises with a programmable and adaptive layer of protection. Its agentic AI model uses automation and context to pre-emptively block sophisticated phishing and malware attacks, giving organisations enhanced control and visibility over their defences.
With the new funding, the company plans to accelerate the development of its AI agents, expand its global operations, and enhance the capabilities of its autonomous email protection systems. The investment will also support hiring across research and engineering to continue evolving the platform’s automated defence ecosystem.
Sublime recently launched two flagship AI agents — the Autonomous Security Analyst (ASA) and the Autonomous Detection Engineer (ADÉ). ASA automatically investigates and triages potential threats in seconds, while ADÉ deploys tailored defences against new attack types within hours, helping organisations avoid costly response delays. These innovations have driven a 100% increase in annual recurring revenue in the first half of 2025 and a 100% enterprise customer retention rate. Clients include global leaders such as Spotify, Snowflake, Zscaler, Anduril, Centrica, British Gas, Elastic, SentinelOne, and Compass.
Sublime Security CEO and co-founder Josh Kamdjou said, “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 defence that detects, triages, and adapts at adversary speed, with the transparency and control that enhances work instead of creating friction.”
Georgian partner Russell Moore said, “We believe that Sublime’s use of agentic AI to counter adversaries is redefining how organisations 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 defences.”
CrowdStrike co-founder and early Sublime investor Dmitri Alperovitch added, “Sublime continues to push the boundary of what we think is possible in email security. They are a true industry disruptor, and as they continue to develop new agentic AI capabilities, legacy solutions will struggle to keep pace.”
ASOS chief information security officer Indu Sajeev said, “What makes the biggest difference is that we’re catching more threats with far less manual work. For a team like ours, having an autonomous platform that adapts to new threats is invaluable.”
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