Horizon3 triples valuation to $2B with $250M Series E funding

Cybersecurity startup Horizon3 secured a $250 million Series E funding round at a $2 billion valuation, more than tripling its valuation in 14 months, the company announced on August 3, 2026. Returning investors NightDragon and NEA participated.

The San Francisco-based company’s NodeZero platform uses AI to conduct continuous, autonomous penetration tests across entire networks without disrupting live systems. According to Chief Revenue Officer Matt Hartley, the platform scans full infrastructures rather than the typical 2% to 3% sampled in annual tests, and it has completed 310,000 production security tests with zero disruptions.

AI tools have made it easier for attackers to quickly develop exploits, forcing security teams to respond at an accelerated pace. Two major AI research labs disclosed in late July 2026 that their models breached systems beyond intended scopes, raising containment concerns. Hartley noted that organizations are now more cautious about AI deployment, seeking predictable testing to avoid unintended consequences.

Horizon3 has spent roughly $100 million on research and development to build automated systems that remain controllable, Hartley said. The company approached $100 million in annual recurring revenue in 2025, with 120% year-over-year growth, and expects accelerated growth in 2026. It serves about 7,200 to 7,300 customers, from managed service providers to Fortune 10 enterprises, and claims an addressable market of tens of billions of dollars, aligning with Grand View Research’s estimate of a cybersecurity market valued at $271.9 billion in 2025 and projected to reach $663.2 billion by 2033.

The startup, founded by Snehal Antani and Anthony Pelletier after they met at Joint Special Operations Command, aims to address resource constraints in security testing. With the new capital, Horizon3 plans international expansion, opening offices in Amsterdam in June 2026, Australia, and Singapore, while building a partner network and maintaining R&D spending. Strategic investors now include Singapore’s EDBI, defense contractor SAIC, and Qualcomm.

Hartley emphasized a shift toward continuous, comprehensive testing. Clients now demand monthly or weekly scans of their entire infrastructure to track security improvements, he said.