Sublime news

Sublime raises $150M Series C to arm defenders for the post-LLM world

October 28, 2025

Sublime raises $150M Series C to arm defenders for the post-LLM world

We’re excited to announce that we’ve raised $150M in Series C funding

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Authors
Josh Kamdjou
Josh Kamdjou
Co-founder & CEO
Ian Thiel
Ian Thiel
Co-founder & COO

It’s been a big year for us here at Sublime. We shipped amazing product like email bomb protection and topic modeling, built AI agents that autonomously triage user reports and auto-adapt coverage, and have grown our team of amazing humans. We’ve grown our customer base 4x since the beginning of the year while maintaining zero enterprise customer churn since company inception. This momentum has led us to today.

We’re excited to announce that we’ve raised $150M in Series C funding to accelerate our vision for an agentic future for email security. The round was led by Georgian, with participation from new investors Avenir, 01A, Jon Oberheide, and Nicole Perlroth, and existing investors Index Ventures, IVP, Citi Ventures, and Slow Ventures.

The Wall Street Journal broke the news this morning. Check out the story here and the full press release.

What this funding enables

Our adversaries often operate like businesses with objectives and resource constraints. Historically these constraints consisted of things like time and skill. With AI, these constraints are gone, enabling more sophisticated, varied, and targeted attacks with less time and skill and higher returns.

We built Sublime to stop this next generation of attacks and fight fire with fire. Our Autonomous Security Analyst (ASA) and Autonomous Detection Engineer (ADÉ) are just the beginning. This funding accelerates our ability to apply the same agentic principles across our platform and deliver more value for our customers.

We're doubling down on what makes Sublime different: email protection that autonomously adapts to each organization's unique environment and evolving threats, with the transparency and control that enhances work instead of creating friction. This means continued investment in platform capabilities that prevent more sophisticated attacks, reduce manual work, and eliminate the vendor bottlenecks of traditional solutions. We're also expanding our global footprint to maximize the impact we have and support customers and partners wherever they operate.

Thank you

We wouldn’t be here without the trust of our customers and security community. Thank you for your support and partnership over the years.

We’re just getting started.

It’s Day 1.

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About the authors

Josh Kamdjou
Josh Kamdjou
Co-founder & CEO

Josh started working for the DoD in high school and spent 10 years engaged in various offensive cyber initiatives and red teaming in the private sector. Phishing was always the fastest way for him to gain access to a network. He started Sublime to build a product that would stop him. Josh holds a B.S. in Computer Science from the University of Maryland. He lives in Washington, D.C. and enjoys weight lifting and spending time with family.

Ian Thiel
Ian Thiel
Co-founder & COO

lan was an early product and growth leader at Optimizely, where he led global go-to-market for new products. Most recently, he ran growth, marketing, and partnerships at Alto. lan holds an M.Sc. in Management from Babson College and a B.Sc. in Economics and Mathematics from York College of Pennsylvania and enjoys hiking, running, and reading.

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Frequently asked questions

What is email security?
Email security refers to protective measures that prevent unauthorized access to email accounts and protect against threats like phishing, malware, and data breaches. Modern email security like Sublime use AI-powered technology to detect and block sophisticated attacks while providing visibility and control over your email environment.

Now is the time.

See how Sublime delivers autonomous protection by default, with control on demand.

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