Nebulock Raises $25M in Series A Funding Led by FirstMark

The round also saw participation from existing backers Bain Capital Ventures, Decibel, Zetta Venture Partners, and Step Function.

The company plans to use the funding to expand its cross-telemetry capabilities, strengthen its behavioral context graph technology, and grow its engineering and enterprise sales teams to meet increasing customer demand.

Nebulock has gained the trust of Fortune 500 companies, leading organizations in industries such as financial services and healthcare, and fast-growing businesses including Cribl, HealthEdge, and Bain Capital.

Its platform has completed more than 300 million automated investigations and identified over 4,000 high-confidence security findings, helping customers prevent incidents. The platform is especially effective at detecting subtle, high-risk behaviors that traditional security tools often miss.

Nebulock is also helping organizations address a new type of insider threat created by the rapid adoption of AI tools in the workplace. Earlier this year, when OpenClaw became widely popular, employees at many companies began downloading and using it, often outside approved security controls.

This created new security risks, including opportunities for attackers to gain access to AI agents and the devices running them. Within a week, Nebulock detected more than 50,000 related events across 40% of its customers and quickly deployed new protections to help prevent incidents linked to this emerging "shadow AI" risk.

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As attackers increasingly use AI to imitate legitimate users and operate with valid credentials, detecting threats has become much harder. Instead of looking only for obvious warning signs, security teams now need to identify suspicious behavior that appears normal. According to the 2026 Verizon Data Breach Investigations Report, attackers are using AI across a growing number of attack techniques.

Nebulock addresses this challenge by combining data from endpoints, identities, cloud services, networks, and SaaS applications. By analyzing activity across these systems, it can detect subtle behavioral patterns that traditional security tools and standard anomaly detection often miss.

“AI is changing both sides of the security equation,” said Damien Lewke, founder and CEO of Nebulock. “The attacker has become more agentic faster than defenders have become proactive. Breaches used to take months; now they take tokens. That’s why Nebulock was built to help security teams move beyond reactive-by-default workflows and toward context-rich, always-on protection that shows them what their stack can’t see. Over time, our vision is much bigger than agentic threat hunting alone—we want to do for SIEM what EDR did for endpoint by collapsing complexity, delivering value out of the box, and up-leveling the defender.”

“The entire security market is at an inflection point,” said David Waltcher, Partner at FirstMark. “From our earliest conversations, it was clear that Damien is the definition of founder market fit, combining deep domain expertise with a rare ability to translate that insight into product, all alongside a world-class team of threat hunters and deeply experienced security experts. As attacks become faster, more credentialed, and more autonomous, enterprises need a new security layer built around context, behavior, and continuous reasoning.

“Security teams need to understand not just what looks suspicious but what look's ordinary for the wrong reasons. Bringing on Nebulock changed the math on how quickly we can detect, and act,” said Myke Lyons CISO of Cribl. When threat intel hits our feeds, the window between awareness and evidence used to be the hardest part to manage. Now that the hunt is run, we have a clear read on exposure, and can remediate before our other tools send us an alert. That shift from assumption to evidence is what a proactive posture actually looks like.”

About Nebulock

Founded by Damien Lewke, Nebulock is an AI-powered security platform that helps organizations detect, investigate, and identify threats across their IT environments. Backed by investors including Bain Capital Ventures, FirstMark, and Decibel, the platform combines security analytics, behavioral analysis and AI driven investigations across endpoint, identity, cloud, network and SaaS environments to uncover threats that traditional security tools often miss.

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