# Horizon3 Funding: How Much It Raised, Its Valuation & Investors

> Horizon3 raised a $250 million Series E at a $2 billion valuation in August 2026, led by NightDragon and NEA. Here's the full breakdown of the round, the backers, and what the autonomous pentesting startup will do with the money.

_[Wortins Blog](https://www.wortins.com/blog) · Published Thursday, August 13, 2026_

**Horizon3 raised $250 million in a Series E round at a $2 billion valuation**, announced August 3, 2026 and led by **NightDragon and NEA**. The round nearly triples the company's valuation from $650 million just 14 months earlier, as AI-driven attacks and defenses push automated security testing into the spotlight.

Here's the full breakdown of the raise, who backed it, and what it means for the cybersecurity market.

## What is Horizon3?

Horizon3 builds an **autonomous penetration testing platform** that uses AI to continuously probe an organization's infrastructure for vulnerabilities — rather than the traditional model of periodic, manual pentests conducted by outside consultants. The company serves **more than 7,000 organizations**, including **four Fortune 10 companies**, giving it a customer base that spans some of the largest enterprises in the world.

## The raise: $250M Series E

The headline numbers:

- **Amount:** $250 million
- **Round:** Series E
- **Valuation:** $2 billion
- **Announced:** August 3, 2026
- **Lead investors:** NightDragon, NEA

For context, Horizon3's prior round was a **Series D at a $650 million valuation** roughly 14 months earlier. Going from $650 million to $2 billion in just over a year is close to a **tripling** of the company's value — one of the steeper valuation climbs among cybersecurity companies in 2026.

## Who invested in Horizon3?

The Series E was led by **NightDragon** and **NEA**. Additional participants included:

- **SAIC**
- **6 other strategic investors**

The presence of SAIC, a major government-focused technology and defense contractor, alongside other unnamed strategic investors suggests Horizon3's customer base extends meaningfully into government and defense contracting, not just commercial enterprise.

## What Horizon3 will do with the money

Horizon3 said the funding will go toward **platform scaling and R&D**. The company has reported **120% year-over-year ARR growth**, a growth rate that typically requires heavy reinvestment in engineering and go-to-market capacity to sustain — which lines up with the stated use of funds.

## Why it matters

1. **Automated security testing is proving out as a durable, well-funded category.** Horizon3's near-tripling of valuation on 120% ARR growth shows investors believe continuous, AI-driven pentesting has become defensible rather than a novelty, a trend also visible in [AI defense tech funding in 2026](/blog/ai-defense-tech-funding-2026).
2. **AI is intensifying both sides of the security arms race.** As attackers increasingly use AI to find and exploit vulnerabilities faster, Horizon3's pitch — using AI to find those same vulnerabilities first — is becoming more urgent, a dynamic echoed in AI-agent security plays like [Zenity](/blog/zenity-funding).
3. **Strategic investors like SAIC signal deepening ties to government and defense budgets**, a customer segment that tends to bring large, sticky contracts and can help justify premium valuations for security infrastructure companies.

Source: [TechCrunch — Horizon3 hits $2 billion valuation with $250M Series E as AI threats escalate](https://techcrunch.com/2026/08/03/horizon3-hits-2-billion-valuation-with-250m-series-e-as-ai-threats-escalate/)

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## Frequently asked questions

### How much did Horizon3 raise?

Horizon3 raised $250 million in a Series E round announced on August 3, 2026.

### What is Horizon3's valuation?

The Series E valued Horizon3 at $2 billion, up from $650 million at its Series D roughly 14 months earlier.

### Who invested in Horizon3?

The round was led by NightDragon and NEA, with SAIC and six other strategic investors also participating.

### What does Horizon3 do?

Horizon3 builds an autonomous penetration testing platform that uses AI to continuously probe infrastructure for vulnerabilities. It serves over 7,000 organizations, including four Fortune 10 companies.

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