The funding comes less than a year after Sublime’s Series B, driven by growing demand for its AI-native email security solutions

Sublime Security, the agentic email security platform, announced that it has raised $150M in Series C funding led by Georgian to accelerate its agentic AI capabilities and bring new levels of proactive, automated defense to email security. Other participants include new investors Avenir and 01A, and existing investors Index Ventures, IVP, Citi Ventures, and Slow Ventures.

This investment comes at a critical time, as phishing and other email-based attacks grow in speed, scale, and sophistication thanks to generative AI. Unlike legacy vendors who offer a rigid, one-size-fits-all solution, Sublime provides a novel approach to email security: a team of specialized AI agents that protect, triage, and adapt defenses in real-time. This new approach frees security teams to focus on their organization’s unique needs, dramatically reducing the resources traditionally required to secure their email environment.

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“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,” said Josh Kamdjou, CEO and Co-founder of Sublime. “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.”

“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,” said Russell Moore, Partner at Georgian. “We’re proud to partner with Sublime as it builds the next generation of proactive and programmable autonomous defenses.”

The Series C funding round follows a period of tremendous growth for the company. In the last six months, Sublime launched its first two AI agents to automate critical security work: its Autonomous Security Analyst (ASA) investigates and triages threats in seconds, freeing teams from manual review, while its Autonomous Detection Engineer (ADÉ) deploys new, tailored defenses to combat novel threats in hours, ending the vendor bottleneck delays that leave organizations exposed.

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Due in large part to these innovations, the company experienced 100% growth in annual recurring revenue in the first half of 2025. This coincides with stellar customer retention, as Sublime has retained 100% of its enterprise customers since its inception, including industry leaders such as Spotify, Snowflake, Zscaler, Anduril, Centrica, Benteler, British Gas, Elastic, SentinelOne, Compass, and more.

“Sublime continues to push the boundary of what we think is possible in email security,” said Dmitri Alperovitch, Co-founder & Former CTO of CrowdStrike and early Sublime investor. “They are a true industry disruptor, and as they continue to develop new agentic AI capabilities, legacy solutions will struggle to keep pace.”

“What makes the biggest difference is that we’re catching more threats with far less manual work,” said Indu Sajeev, Chief Information Security Officer, ASOS. “For a team like ours, having an autonomous platform that adapts to new threats is invaluable.”

In addition to doubling down on platform enhancements and adding to its team of AI Agents, Sublime will use this latest funding round to grow its global footprint and make life harder for adversaries worldwide.