Island raises $400M Series F at $6.4B valuation to govern AI agents alongside human workers

Dallas-based Island has raised a $400 million Series F led by Evolution Equity Partners, more than doubling its valuation since 2024 to $6.4 billion and pushing its total funding past $1 billion.¹² Existing backers Prysm Capital, Sequoia Capital, Coatue Management, Cyberstarts, Insight Partners, J.P. Morgan Growth Equity Partners, Alta Park Capital, Georgian, G Squared and Squarepoint all returned for the round, alongside a personal investment from cybersecurity entrepreneur Dmitri Alperovitch.¹ CEO and co-founder Mike Fey told CNBC the money will fund international expansion into Europe, Asia and the Middle East and grow headcount from 1,000 to 1,500 by mid-2026.³

Island built the first enterprise browser — letting companies monitor and control what employees do inside it — and has since extended that into data-loss prevention and a next-generation SASE architecture covering endpoints and networks.¹² The pitch now is a single "control plane" that governs both human employees and the AI agents increasingly working alongside them: zero-trust network access, device posture checks, and DLP rules that block unapproved clipboard transfers or downloads, plus guardrails that keep proprietary data away from external language models and mitigate prompt-injection risk.² Fey said demand is being driven by enterprises racing to secure themselves against "swarms of rogue AI agents," pointing to OpenAI's agent-orchestrated attack on Hugging Face as the kind of incident customers are now trying to get ahead of.³ Island counts Pfizer, Chipotle, American Airlines and major banks among its customers.³

Evolution Equity Partners, which closed a record $1.1 billion dedicated cybersecurity fund in 2024, has built a portfolio squarely in Island's neighborhood: cloud security firm Aqua Security, managed-detection provider Arctic Wolf, ratings firm SecurityScorecard, code-security player Snyk, cloud-runtime specialist Sweet Security, and — most directly relevant to Island's new pitch — Protect AI, which secures AI/ML systems themselves.⁴ Firm founder Richard Seewald said Island "can see and govern what people and agents are doing as they interact with applications and data, wherever that happens," framing the deal as an extension of that AI-security thesis rather than a one-off bet.¹

Why it matters: Evolution's largest-ever cybersecurity fund now anchoring Island's leap from browser security to full "agentic control plane" shows dedicated cyber-VC capital following enterprises' AI rollout in real time — chasing the governance layer for AI agents as hard as it once chased endpoint and cloud security.