Horizon3.ai announced a $250 million Series E on August 3 at a valuation of more than $2 billion, tripling its Series D mark of $650M in just over a year. The oversubscribed round was co-led by existing investors NightDragon and NEA with participation from seven new backers including Acrew Capital, EDBI, PSG, SAIC and Sapphire Ventures, plus returning investors Craft Ventures, Prosperity7 Ventures, Qualcomm Ventures, Ridge Ventures and SignalFire.
NodeZero And The AI-vs-AI Pitch
Horizon3.ai's NodeZero platform autonomously pentests production networks without humans in the loop, chaining together misconfigurations, weak credentials and identity gaps to prove exploitable attack paths — then instantly verifies remediations. The company says it has now executed 310,000 tests in production and protects more than 7,000 organizations including four Fortune 10 enterprises, multiple multinational banks and major healthcare networks, growing ARR 120% year over year.
NightDragon Doubles Down
As part of the round, NightDragon founder Dave DeWalt — a former CEO of FireEye and McAfee — and NightDragon managing director Morgan Kyauk join the Horizon3 board. "Snehal and his team have built an unparalleled proactive security platform that is fundamentally reshaping how the world defends its data," DeWalt said. NightDragon has previously led rounds in Epirus and Classiq.
Use Of Proceeds
Horizon3.ai will scale go-to-market across enterprise, mid-market and federal customers, open offices in Singapore and Australia and deepen its EMEA presence. The next-generation roadmap includes autonomous blue-team agents that remediate NodeZero findings directly, extending the platform from pentesting into a continuous AI attacker-defender loop. The company is FedRAMP High authorized and has been named one of Fast Company's Most Innovative and the Fastest Growing Cybersecurity Company in North America by the Deloitte Technology Fast 500. The Series E adds to a busy stretch of AI-security fundraising alongside Corma's $60M seed.
Reporting based on coverage from Horizon3.ai, Business Wire, TechCrunch and Forbes.