October 2025 marks a pivotal moment for enterprise email defense: Sublime Security has pulled in $150 million in Series C funding, with Georgian leading and significant support from Avenir, 01A, Index Ventures, IVP, Citi Ventures, and Slow Ventures.
This investment arrives as generative AI—once a bleeding-edge tool—now fuels both waves of attack and defense across the cybersecurity sector.
From Pentagon Roots to a Surge in Adoption
The Sublime founding story is anything but ordinary. CEO Josh Kamdjou, who spent nearly a decade as a Department of Defense offensive hacker, was haunted by a frustrating truth: breaking into Fortune 500 companies was almost embarrassingly easy using phishing emails.
Alongside co-founder Ian Thiel, Kamdjou launched Sublime in 2019 to empower defenders with the adaptability they saw on the offensive side.
Bringing hacker insight to mainstream security, Sublime now protects organizations like Netflix, Snowflake, Roche, and Anduril.
In the past year alone, the company quadrupled its customer count with zero enterprise churn—a lightning growth pace that speaks to its urgency and fit in the market.
Sublime Security Funding Rounds
| Round | Amount | Lead Investors | Date |
|---|---|---|---|
| Series C | $150M | Georgian | Oct 2025 |
| Series B | $60M | IVP | Dec 2024 |
| Series A | $20M | Index Ventures | Apr 2024 |
| Seed | $9.8M | Decibel Partners, Slow Ventures | Feb 2023 |
The Arms Race: Autonomous Agents vs. Automated Attackers
What’s different about Sublime is its vision for “agentic” security. While other vendors tack on AI-powered features, Sublime has built its entire platform around autonomous agents—digital defenders that triage, adapt, and evolve as fast as attackers change tactics in the wild.
Core to this is the duo of ASA (Autonomous Security Analyst) and ADE (Autonomous Detection Engineer).
These agents don’t just detect known threats—they proactively respond to new attack types and help defenders craft real-time detection strategies, making legacy, rule-based systems look ponderous and static by comparison.
The Capital Is Fuel for Expansion—And for a New Security Playbook
While large rounds are becoming less rare in cybersecurity, this level of backing signals a shift in what customers and investors expect.
The arms race between attackers using generative AI and defenders using autonomous AI tools is escalating quickly.
Sublime’s new funding is earmarked not just for product, but also for stepping further into global markets and scaling its go-to-market engine. The addition of Colin Jones (former Wiz Chief Revenue Officer) to run sales signals their intent to scale fast in a hotly contested sector.
Key Facts Investors & Candidates Ask About
| Parameter | Detail |
|---|---|
| Series C | $150 million, led by Georgian, joined by Avenir, 01A, Index, IVP, etc. |
| Total Raised | $243.8 million |
| Valuation | Undisclosed (significantly up from last year’s $93.8M post-Series B) |
| Customer Growth | 4x increase in 2025, zero enterprise churn |
| Tech Focus | Autonomous agentic email security, open detection language, API-first |
| Founders | Josh Kamdjou, Ian Thiel |
| HQ | Washington, D.C., USA |
All Eyes on the Next Chapter
With this fresh capital, Sublime Security faces two big tests: staying ahead in the AI-powered threat arms race and proving that an agentic defense platform can scale with the world’s largest organizations.
Transparency, programmability, and relentless attacker empathy remain Sublime’s calling cards.
If the company sustains its current trajectory, competitors tied to black-box or static email security tech may soon be left behind.
Connect with Sublime Security
| Platform | URL |
|---|---|
| Website | https://sublime.security |
| https://www.linkedin.com/company/sublime-security | |
| Blog | https://sublime.security/blog |
| GitHub | https://github.com/sublime-security |
