Sources: South Korean AI chip designer DeepX raised a ~$29M Series D at a ~$2.2B valuation, and is in talks to raise ~$209M at a ~$2.4B valuation by September (Yoolim Lee/Bloomberg)

Cybersecurity firm Horizon3 has just achieved a $2 billion valuation, thanks to a $250 million investment in its Series E round. This represents a significant leap from its previous valuation, which surged more than threefold within a 14-month span. Headquartered in San Francisco, the company has been bolstered by the backing of NightDragon and NEA, two prominent investors. The influx of funding comes amid growing concerns over breaches caused by AI models venturing beyond their intended boundaries.

Horizon3 has been honing its expertise for six years, with the goal of developing AI specifically designed for probing networks for vulnerabilities in a controlled, authorized fashion. The market demand for such AI-driven security solutions is on the rise, as enterprises scramble to stress-test their defenses at scale. Traditional security vendors have largely failed to address this need.

Matt Hartley, Horizon3's chief revenue officer, noted that the company's NodeZero platform has two key advantages: it can test live systems without disrupting operations, a feat not reliably achieved by other AI-powered tools, and it continuously scans the entire infrastructure, as opposed to the traditional once-a-year scans that focus on just 2-3% of the network.

The company's annual recurring revenue hit $100 million last year, reflecting a 120% year-over-year growth. This trend is expected to continue in the coming year.

The acceleration of AI-driven attacks has pushed security teams to handle threats more swiftly than they can remediate them. Horizon3 spent about $100 million on R&D to build automated systems that remain predictable and controllable. Given the recent AI-related breaches, this investment has proven crucial. Hartley emphasized that the heightened awareness of AI's potential risks has led organizations to question their deployment strategies and consider the ramifications of aggressive deployments.

As a result, many are adopting a more cautious approach, seeking consistent and predictable testing from a company like Horizon3 to strengthen their defenses against real-world exploits.

According to Hartley, Horizon3's "AI Hackers" represent a novel approach to penetration testing, with fully autonomous systems that have conducted 310,000 production security tests without causing any disruptions. The real competition, Hartley contends, lies not with other software vendors, but in the conventional practice of hiring human security firms for annual tests.

The demand from clients has shifted from sampling 5% of infrastructure annually to scanning everything monthly or weekly, ensuring they are genuinely becoming safer over time.

Founded by Snehal Antani and Anthony Pillitiere, who previously worked together at Joint Special Operations Command, Horizon3 was created to automate repetitive security assessments that were previously difficult to manage due to resource constraints. With the new funding, the company plans to expand internationally, opening new offices in Amsterdam, Australia, and Singapore, while continuing to invest heavily in research and development.

Strategic investors in Horizon3 now include EDBI from Singapore, defense contractor SAIC, and Qualcomm, underscoring the broad relevance of the vulnerability Horizon3 is addressing. The company has approximately 7,200 to 7,300 customers, ranging from managed service providers serving small businesses to Fortune 10 enterprises. Horizon3 claims an addressable market worth tens of billions of dollars, aligning with industry estimates of the overall cybersecurity market, which was valued at $271.9 billion in 2025 and projected to reach $663.2 billion by 2033.