Island raised $400 million in a Series F round at a $6.4 billion valuation on September 24, extending its enterprise browser business into security controls for AI agents. The financing arrives seven months after a $250 million Series E and tests whether customers will trust a browser company to govern how automated agents interact with corporate applications, endpoints, and data.
From browser security to agent governance
Island's founders built the company on a straightforward premise: the browser is enterprise infrastructure that security teams have long treated as someone else's product. Co-founders Dan Amiga and Mike Fey designed a purpose-built work environment with security, access, and data controls embedded directly into the software employees already use. Amiga, Island's CTO, now argues that the browser is a starting point for controlling a larger problem - people and software agents acting across company systems.
The Series F announcement describes Island as an "agentic control plane" for enterprises. The stated goal is to apply one policy system and audit trail across browsers, endpoints, applications, networks, and data, including when an AI agent performs the work. An agent that can interact with corporate applications may also reach sensitive information or take actions under an employee's authority. Island says its approach brings identity, access rules, data boundaries, approvals, and auditability together. The funding announcement does not specify how many customers use the broader agent-control offering or what share of revenue it contributes.
The founder pairing behind the strategy
Amiga and Fey's working relationship predates Island. Amiga founded Fireglass, a secure-browsing startup that Symantec acquired in 2017. Fey, then Symantec's president, was on the acquiring side. The two later co-founded Island, with Fey as CEO and Amiga leading technology. In a September interview with Calcalist, Amiga described their complementary strengths: Fey brought experience in sales, marketing, and managing a US-based operation; Amiga said he preferred building products.
That pairing has now produced a company employing 1,000 people. Island said it has doubled annual recurring revenue every fiscal year since its 2022 launch. Amiga told Calcalist earlier in September that Island had about $200 million in revenue and was growing roughly 100% annually. The metrics come from different descriptions of performance, and neither announcement supplies audited financials or detail on revenue mix.
What the round and valuation signal
Evolution Equity Partners led the Series F, with existing investors Prysm Capital, Sequoia Capital, Coatue Management, Cyberstarts, Insight Partners, J.P. Morgan Growth Equity Partners, Alta Park Capital, Georgian, G Squared, and Squarepoint participating. Cybersecurity entrepreneur Dmitri Alperovitch also made a personal investment, Reuters reported. The $6.4 billion valuation is one-third higher than the $4.8 billion mark set in March 2025. A valuation records the terms investors accepted for a private financing; it does not by itself show whether the expanded product strategy will translate into durable adoption.
Island emerged from stealth in February 2022. The enterprise browser was a direct challenge to the assumption that companies should accept consumer browsers and layer security tools around them. Agent governance reaches into controls already managed across identity, endpoint, network, and data-security products. Island's pitch is that those layers need a shared view of what people and agents are doing. Whether customers buy that as a unified platform, or keep assembling controls from incumbent vendors, is the commercial test behind the new valuation.
The $400 million gives the founders more room to pursue their wager: build a standalone company around the browser, then extend that foothold into the rest of enterprise work. Customer adoption of the broader control layer will determine whether it becomes more than an expanded description of the original browser business.
Why this matters for IT and development leaders
Island's move from browser security to agent governance signals a shift in how vendors are positioning infrastructure for AI workloads. IT and development teams evaluating agent deployments will face decisions about whether to manage agent access through existing identity, endpoint, and network tools or through a unified control layer. The round also shows investor appetite for security platforms that treat both human users and automated agents as subjects of the same policy framework - a design choice that could influence procurement patterns as agent adoption grows. For teams building or buying AI agents, the funding reinforces that access controls, audit trails, and data boundaries for non-human actors are becoming a distinct product category rather than an afterthought. Leaders planning AI IT strategy training may want to watch whether unified control planes gain traction over point solutions.
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