Island raises $400m Series F at $6.4bn valuation

The round

Evolution Equity Partners led the round, with Sequoia Capital, Coatue Management, Cyberstarts and Insight Partners among the existing investors that joined. Returning backers also included Prysm Capital, J.P. Morgan Growth Equity Partners, Alta Park Capital, Georgian, G Squared and Squarepoint, and Dmitri Alperovitch made another personal investment. Island said the capital will fund product development and continued growth beyond the browser.

From browser to control plane

Island began with an Enterprise Browser that put security, access and productivity controls inside the window employees already used. It has since added data protection, data loss prevention and SASE, and extended controls to consumer browsers and endpoints. The company now calls the bundle an agentic control plane: a shared security, governance and auditing layer for employees and for AI agents.

The layer runs on one policy engine and one audit trail across browsers, endpoints, applications, networks and data. Dan Amiga, the CTO and a co-founder, listed five components: last-mile control, network, data, identity and observability. Island pitches the architecture as an alternative to running AI security through separate tools at different points in the stack.

The case for the browser, and its limit

An AI agent working inside a web application passes through a browser, which makes the browser a possible enforcement point, GCN reported. Agents can reach across applications, data and internal systems, creating governance problems that employee-only controls were not built for. Island controls the browser itself rather than monitoring APIs or sandboxing, Yahoo Finance reported. That outlet framed the choice as browser-native control against API-level monitoring, naming Dataiku and SAP as monitoring vendors and NiCE Cognigy as a routing tool.

CEO Mike Fey made the case in the announcement:

"We've entered a new era in which people and AI agents work side by side. Just like humans, agents need the right context, access, guardrails, and accountability to succeed."

GCN noted the limit to that argument: Google bundles equivalent controls into Chrome and Microsoft into Edge for Business, included in Microsoft 365 at no extra cost. Free and built-in is a hard price to beat, it said.

The valuation arithmetic

Island says $6.4 billion more than doubles its 2024 valuation. The figure is 33% above the $4.8 billion valuation set in its Series E round in March 2025, Yahoo Finance reported. Total funding is above $900 million, according to that outlet; Pulse 2.0 put the cumulative figure at approximately $1 billion. Island employs about 1,000 people and says annual recurring revenue has doubled every fiscal year since its 2022 launch.

What is not disclosed

No absolute ARR figure was disclosed, so the $6.4 billion price has no public revenue denominator. Island said millions of users rely on its technology.