Horizon3 Raises $250M Series E at $2B+ Valuation to Lead the “AI vs. AI” Cybersecurity Era

NightDragon and NEA Co-Lead Oversubscribed Round; Company triples valuation and surpasses 7,000 customers amid 120% ARR growth

SAN FRANCISCO--(BUSINESS WIRE)--Horizon3, the AI-Native Proactive Security Company behind NodeZero®, the World’s Best AI Hacker™, today announced a $250 million Series E at a valuation of more than $2 billion, tripling its valuation from $650 million at Series D in just over a year. The oversubscribed round was co-led by existing investors NightDragon and NEA, with participation from seven new investors and five returning backers. The capital underscores accelerating global demand for safe, autonomous security validation as AI-driven cyberattacks escalate.

“We invented the concept of AI Hackers and spent six years earning the right to autonomously pentest the most critical and sensitive networks in the world — with no humans in the loop,” said Snehal Antani, Co-Founder and CEO of Horizon3. “Our massive data moat – built on 310,000 tests safely executed in production – combined with thousands of radical champions who love our product, has allowed us to achieve consistent top-tier financial and operational metrics. This round gives us the fuel to scale aggressively as the definitive leader of the AI vs. AI era.”

A Defining Moment for Autonomous Security

Cyberattacks now move at the speed of AI, and traditional defenses cannot keep pace. Horizon3’s NodeZero platform closes that gap by autonomously and safely attacking an organization’s own production environment. It reveals exactly how adversaries chain together misconfigurations, weak credentials, and identity gaps to compromise critical systems, provides fix guidance, and instantly verifies remediation. Additionally, as NodeZero tests an environment, it can optimally deploy honeypots that are the cheapest, fastest, and most effective way of detecting AI attackers and prove they are inside.

This unique approach has powered 120% year-over-year ARR growth as Horizon3 now protects over 7,000 organizations globally including multinational banks, major healthcare networks, and four Fortune 10 enterprises. Vetted, tested, and operational across large, classified government agencies and enterprises in the most highly regulated industries in the world, Horizon3 is FedRAMP® High authorized and helps organizations meet DORA, NIS 2, NIST CSF 2.0, HIPAA, SOC 2, and GDPR regulatory requirements. The company was also recently named the Fastest Growing Cybersecurity Company in North America by the Deloitte Technology Fast 500 and named one of the Most Innovative companies by Fast Company in 2026.

Premier Global Investor Syndicate and Board Additions

The Series E round was co-led by existing investors NightDragon and NEA, with participation from a syndicate of new and returning strategic and institutional investors:

• New investors: Acrew Capital, Blue Cloud Ventures, Demeter Group, EDBI (Singapore), PSG, SAIC, and Sapphire Ventures
• Existing investors: Craft Ventures, Prosperity7 Ventures, Qualcomm Ventures, Ridge Ventures, and SignalFire

As part of the investment, Dave DeWalt, Founder and CEO of NightDragon and former CEO of FireEye and McAfee, and Morgan Kyauk, Managing Director at NightDragon, will join Horizon3's Board of Directors.

“Horizon3 coined the concept of cyber warfare being AI vs. AI, and that future has arrived,” said Dave DeWalt. “Snehal and his team have built an unparalleled proactive security platform that is fundamentally reshaping how the world defends its data. I am thrilled to join the board to help Horizon3 secure the world's most critical infrastructure and enterprises at scale.”

“Horizon3 has demonstrated textbook operational excellence,” said Morgan Kyauk. “They have built an incredibly efficient, highly scalable go-to-market motion that will be further amplified by NightDragon's ecosystem of partners, advisors, and global customers.”

Use of Proceeds

Horizon3 will deploy the new capital across three strategic priorities:

• Aggressive GTM Scaling: Scaling go-to-market operations — sales, marketing, and channel — to meet surging global demand across enterprise, mid-market, and federal customers.
• International Expansion: Strategic entry into Singapore and Australia while deepening presence across EMEA.
• Next-Gen Product Innovation: Accelerating the product roadmap to build a continuous learning loop between AI Attackers and AI Defenders — including new autonomous blue-team agents that remediate findings directly from NodeZero pentests.

“It has never been harder for CIOs and CISOs. Attackers are getting faster, enterprise IT is becoming more complex, and regulators and cyber insurers are becoming more punitive,” Antani added. “We're about to see an explosion of vulnerabilities, most of which won't matter, but a small percentage will be immediately exploitable. The goal of running pentests isn’t to find problems, it’s to quickly fix exploitable problems that matter. We started with pentesting, evolved to be a proactive security platform, and will now accelerate remediation by creating AI learning loops between attackers and defenders.”

About Horizon3

Horizon3, the AI-Native Proactive Security Company behind NodeZero®, shifts the advantage from attackers to defenders by giving organizations the power to fight AI with AI. NodeZero, the World's Best AI Hacker™, autonomously tests defenses at machine speed, safely uncovers and prioritizes exploitable attack paths, instantly verifies fixes, and drives a continuous hack, fix, verify loop. More than 7,000 organizations, including global defense agencies, Fortune 10 enterprises, multinational banks, and major healthcare providers, trust Horizon3 for security they can prove. Horizon3 was recently named the Fastest Growing Cybersecurity Company in North America by the Deloitte Technology Fast 500 and named one of the Most Innovative companies by Fast Company in 2026. Follow Horizon3 on LinkedIn and X.