Horizon3 Raises $250M Series E at $2B Valuation

Horizon3, a San Francisco-based AI-native proactive security company, has raised $250 million in a Series E funding round, bringing its total valuation to $2 billion. The company provides the NodeZero platform, which uses autonomous AI to simulate cyberattacks and help organizations identify and remediate security vulnerabilities.

Investors

The round was co-led by existing investors NightDragon and NEA. Additional participating investors include new backers Acrew Capital, Blue Cloud Ventures, Demeter Group, EDBI (Singapore), PSG, SAIC, and Sapphire Ventures, as well as returning investors Craft Ventures, Prosperity7 Ventures, Qualcomm Ventures, Ridge Ventures, and SignalFire.

Horizon3 Use of Funds

Horizon3 plans to use the capital to aggressively scale its go-to-market operations across enterprise, mid-market, and federal sectors. The company will also focus on international expansion into Singapore, Australia, and EMEA, while accelerating product innovation to build autonomous blue-team agents that automate the remediation of security findings.

About Horizon3

Founded in San Francisco, Horizon3 develops NodeZero, an AI-powered autonomous penetration testing platform that enables organizations to continuously identify, validate, and remediate exploitable security vulnerabilities. The platform safely simulates real-world cyberattacks, helping enterprises, government agencies, financial institutions, and healthcare organizations strengthen their cyber defenses through automated security testing and continuous validation.

Funding Details

Company Website: https://horizon3.ai

Company: Horizon3
Raised: $250M
Round: Series E
Funding Date: August 2026
Lead Investor: NightDragon, NEA
Additional Investors: Acrew Capital, Blue Cloud Ventures, Demeter Group, EDBI (Singapore), PSG, SAIC, Sapphire Ventures, Craft Ventures, Prosperity7 Ventures, Qualcomm Ventures, Ridge Ventures, SignalFire
Company Website: https://www.horizon3.ai
Software Category: Cybersecurity
Source: https://www.businesswire.com/news/home/20260803793896/en/Horizon3-Raises-%24250M-Series-E-at-%242B-Valuation-to-Lead-the-AI-vs.-AI-Cybersecurity-Era