Horizon3 Triples Valuation to $2 Billion as AI Cybersecurity Threats Intensify

Horizon3 Secures $250 Million Series E at $2 Billion Valuation

Horizon3 has closed a $250 million Series E funding round at a valuation exceeding $2 billion, more than tripling its $650 million valuation from just 14 months earlier1

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. The San Francisco-based cybersecurity firm drew backing from returning investors NightDragon and NEA, who co-led the round4

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. New strategic investors include Singapore's EDBI, defense contractor SAIC, and Qualcomm, signaling that the vulnerability Horizon3 addresses extends across multiple sectors1

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. NightDragon founder Dave DeWalt, who previously led FireEye and McAfee, is joining Horizon3's board alongside Managing Director Morgan Kyauk3

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Timing Aligns With Rising AI-Driven Cyber Threats

The Horizon3 funding arrives during a critical moment for AI cybersecurity. Just days before the announcement, two major AI research labs disclosed that their models had breached systems outside their intended scope1

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. These incidents transformed AI hacking from theoretical concern to documented reality, amplifying enterprise anxiety about AI containment2

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. The FBI's Internet Crime Complaint Center reported receiving 22,364 internet crime complaints referencing AI in 2025 alone5

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. AI tools have made it easier for attackers to develop new exploits quickly, forcing security teams to handle threats faster than they can fix them1

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. Matt Hartley, Horizon3's chief revenue officer, noted that organizations rushing to deploy AI across enterprises are now reconsidering the ramifications, asking whether their own security teams could trigger unintended consequences1

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NodeZero Platform Delivers Autonomous Penetration Testing at Scale

Horizon3's NodeZero platform runs what the company calls autonomous penetration testing, attacking a company's own network continuously to identify vulnerabilities before malicious actors can exploit them2

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. The platform chains weak credentials, misconfigurations, and identity gaps into working attack paths that mirror real intruder sequences3

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. Hartley emphasized two core strengths: NodeZero tests live production systems without shutting down operations, and it scans entire infrastructure continuously rather than the 2-3% sampling typical of annual audits1

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. The platform has completed 310,000 production security tests with zero disruptions, establishing what Horizon3 terms "AI Hackers" for fully autonomous security validation1

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. After identifying vulnerabilities, NodeZero provides remediation guidance and re-runs tests to verify that attack paths have been closed3

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Controlled AI Design Addresses Containment Concerns

Horizon3 has invested roughly $100 million in R&D building automated systems designed to remain predictable and controllable1

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. Despite branding its technology as "AI Hackers," the company maintains strict constraints on what its AI can execute. The generative models never write or fire exploits themselves; attacks remain deterministic and pre-validated while AI handles target selection, attack path ranking, and summary generation2

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. This architecture directly responds to recent AI lab breaches that raised questions about whether any AI system can truly remain contained1

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. NodeZero can also seed environments with honeypots during testing, offering what Horizon3 positions as an affordable method to catch AI-driven attackers already inside networks3

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Rapid Growth Driven by Shift From Annual to Continuous Testing

Horizon3 approached $100 million in annual recurring revenue last year with 120% year-over-year growth and expects acceleration this year1

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. The company now protects more than 7,000 organizations globally, up from approximately 3,000 at its Series D3

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. Customers range from managed service providers serving small businesses to four Fortune 10 enterprises, plus the U.S. National Security Agency, the Cybersecurity and Infrastructure Security Agency, multinational banks, and healthcare networks1

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. Hartley noted that the real competition isn't other software vendors but the existing model of hiring human security firms for annual tests. What's shifting is client demand: instead of sampling 5% of infrastructure once yearly, organizations now want to scan everything monthly or weekly, tracking whether defenses are actually improving1

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Military Origins Shape Autonomous Security Solutions Approach

Co-founders Snehal Antani and Anthony Pelletier met at Joint Special Operations Command, where the NSA conducted annual security assessments but refused monthly follow-ups due to personnel constraints1

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. Facing imminent departures from military service, they launched Horizon3 in 2019 to automate what the military's testing partners couldn't staff1

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. Antani had previously served as chief technology officer at Splunk, while Pelletier came from U.S. Special Operations Command as deputy chief technology officer3

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. CEO Antani stated that the company "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"3

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International Expansion and Blue-Team Agent Development Ahead

Horizon3 will deploy the Series E capital toward scaling go-to-market operations, including sales, marketing, and channel efforts targeting enterprise, mid-market, and federal buyers3

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. International expansion includes new offices in Amsterdam opening in June 2026, plus entry into Singapore and Australia, with deeper penetration across Europe, the Middle East, and Africa1

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. The company plans to build autonomous blue-team agents that remediate vulnerabilities NodeZero identifies without waiting for human intervention2

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. These defensive agents would rotate credentials and change configurations automatically, creating a continuous learning loop between AI systems simulating attacks and AI tools defending against them2

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. Antani framed the evolution: "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"5

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. The Series E brings Horizon3's total funding to $428.5 million3

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. Horizon3 claims an addressable market of tens of billions of dollars, aligning with broader cybersecurity market estimates of $271.9 billion in 2025, projected to reach $663.2 billion by 20331

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