Sublime Security: Reinvesting in the future of email protection

It has been less than a year since our first investment in Sublime Security’s Series B funding round. During that time, the company has outperformed our optimistic expectations, attracting top talent, adding large enterprises and best-in-class startups as customers.

What initially attracted us to Sublime was the flexibility of its AI-powered email security platform, with its ability to adapt to dynamic threats in real time vs. traditional blackbox approaches. We highlighted Sublime’s open architecture, which gives security teams the transparency and flexibility to construct specific detection rules to the threats their business faces. In addition, we noted that the company deploys via API, directly connecting to Google or Microsoft email systems, allowing companies to quickly integrate the platform and start realizing value without lengthy implementation cycles.

What is clear is that since our initial investment, Sublime’s customizable approach to email security has resonated with users, helping them act quicker, take a forward-looking approach to security and access a like-minded community that collectively shares solutions to address cyber threats.

Key Operational and Strategic Decisions

While Sublime had a phenomenal product that gained traction with users, it needed a special person to take the company to the next level. That game-changing hire came in the form of President Colin “CJ” Jones. Jones, formerly CRO at Wiz, one of the fastest growing startups of all time, where he helped grow the pioneering cloud security company from zero to $100M of ARR. CJ joined as Sublime’s first President, and he immediately hit the ground running late last year.

Around that time, Sublime made another pivotal decision: fully integrating AI agents into its products to not only work in the background but to help users maximize all product features. Sublime released its autonomous detection engineer (ADÉ), which analyzes evolving attacks and iteratively generates and backtests new detection coverage. Earlier this year they also launched the autonomous security analyst (ASA), which automates end-to-end user report investigations, conducting detailed analysis, replying to users, and resolving or remediating reports – including quarantining malicious messages and intelligently grouping similar messages for efficient campaign remediation based on a single report.

Growing Customer Base

Sublime’s strong out-of-the-box efficacy and innovative product suite has helped attract best-in-class startups such as Cribl and Snyk, both Citi Ventures portfolio companies, as well as leading public companies including Spotify, Zscaler, and Snowflake.

We are proud of Sublime’s success and excited to participate in another funding round for the company. Citi Ventures is delighted to welcome new investors in the Series C, Georgian, 01A, and Avenir Growth, and is proud to support Sublime alongside existing investors, Index Ventures, IVP, and Decibel, as Sublime continues its journey to support a new approach to email security.