On September 24, 2026, Island, the company that popularized the term "enterprise browser," announced a $400 million Series F that brings its valuation to $6.4 billion, more than double the $3 billion it was valued at in 2024. The round was led by Evolution Equity Partners, with existing backers Sequoia Capital, Coatue Management, Cyberstarts, Insight Partners, J.P. Morgan Growth Equity Partners, Alta Park Capital, Georgian, G Squared, Squarepoint and Prysm Capital all returning, plus a personal investment from cybersecurity investor Dmitri Alperovitch. The headline framing from the company is not "we secure browsers a little better." It is that Island now sees itself as an "agentic control plane," a single policy and audit layer that governs both employees and AI agents as they move across browsers, applications, networks and data.
That combination, a security company built around a browser now repositioning around AI agents, is worth unpacking on its own terms: what an enterprise browser actually does, why the browser is turning into a plausible enforcement point for agentic work, and what a valuation north of 30 times revenue says about how this market is currently being priced.
What an enterprise browser actually is
A regular browser is a piece of client software that renders web pages and otherwise stays out of the way. An enterprise browser is the same rendering engine, Island's is built on Chromium, the open-source project underlying both Chrome and Edge, wrapped in a layer of controls that a security or IT team can configure and audit: which sites and applications a user can reach, what they can copy, paste, upload or download inside a session, whether a screenshot or a print action is even possible on a sensitive page, and a continuous log of what happened. Because so much of modern enterprise work already happens inside a browser tab rather than a locally installed application, putting controls at that layer gives a security team visibility and enforcement over software-as-a-service tools, internal web apps and contractor access without having to touch the underlying network or the application itself. Island says eight of the world's ten largest banks use its enterprise browser today, a customer base that reflects how much of that appeal has landed with the most heavily regulated buyers first.
Why the browser is becoming the agent enforcement point
The pitch for treating the browser as an AI agent control point follows directly from how most agents actually work today. An agent that books travel, files an expense report, pulls data from a SaaS dashboard or fills out a form is very often doing that through the same web interface a human employee would use, either by driving a browser directly or by calling the same authenticated session a person is logged into. That makes the browser one of the few places a company can observe and constrain what an agent is doing regardless of which model or vendor built it: what it is allowed to read, what it can paste or export, which applications it can reach under whose identity, and for how long a given session or credential stays valid. Island's chief technology officer and co-founder, Dan Amiga, put the argument this way when the round was announced: agents do not operate in a single layer, and the company's pitch is a control plane that unifies identity, access, data boundaries, approvals and audit trails across devices, browsers, applications, networks and data, whether the actor at the keyboard is a person or an agent.
Three rounds, valuation up more than 2x
Island's disclosed valuation at each of its last three funding rounds. It more than doubled from its 2024 Series D to the September 2026 Series F.
The Series F was led by Evolution Equity Partners, with Sequoia Capital, Coatue Management and other existing backers participating.
Agents do not operate in a single layer. Island's control plane unifies five critical layers.
Dan Amiga, co-founder and CTO, Island
Where this sits in the broader agent-security funding wave
Island's repositioning is one entry in a wider pattern of security vendors racing to define the control point for enterprise AI agents, and it is worth placing next to two other deals from earlier this year. In July 2026, Cyera agreed to acquire the identity-focused startup Oasis Security for about $1 billion, betting that non-human identity, provisioning and governing the credentials an agent uses to authenticate, would be the layer that mattered most. In August 2026, Okta shipped Agent SSO, giving agents a first-class identity in the same directory as human employees and issuing short-lived, policy-scoped tokens rather than standing API keys. Island's bet is adjacent but distinct: rather than starting from identity or from data classification, it starts from the browser session itself, the place where an agent's access, its actions and its outputs are all visible at once. None of these approaches is mutually exclusive, and the fact that well-funded companies are converging on identity, data and browser sessions as three separate entry points into the same problem is itself a sign that no single layer has yet proven decisive.
For teams building with AI agents rather than selling security tools to them, the practical takeaway is closer to home than the funding round. As agents multiply across more tools and more sessions, keeping a consistent, portable view of what each one is allowed to touch matters as much as which model is doing the reasoning. Platforms like Metir AI, which let a team work across multiple leading models from one governed workspace instead of scattering agent access across disconnected point tools, are a response to the same underlying pressure that is pulling capital toward Island, Cyera and Okta: as agent identities and agent sessions multiply, the value shifts toward whichever layer can see and govern all of them consistently.
Reading the multiple honestly
At $6.4 billion on roughly $200 million in reported annual revenue, Island is priced at close to 32 times its trailing revenue, a multiple that sits at the high end even for the current AI infrastructure market. The company says that revenue is growing at roughly 100% a year and that annual recurring revenue has doubled in every fiscal year since it launched in 2022, and if that growth rate holds, the multiple compresses quickly on its own. That is also precisely the bet embedded in every round like this one: growth this fast justifies pricing on where the business is headed rather than where it stands today, and multiples of this size have become close to standard across the small set of companies perceived as leaders in agent-facing security and infrastructure this year, not a one-off anomaly specific to Island.
The counterweight deserves equal billing. A pivot from "the best way to secure a browser" to "the control plane for enterprise AI agents" is a considerably larger claim, and it puts Island in more direct competition with identity vendors, data-security vendors and the AI platforms themselves, several of which are building their own governance and audit layers natively rather than depending on an external browser. Recognition such as Frost & Sullivan naming Island its 2026 Global Zero Trust Browser Security Company of the Year and a Gartner Peer Insights Customers' Choice award for secure enterprise browsers speaks to a strong position in the market it already competes in. Whether that position extends cleanly into the broader agent-governance category it is now reaching for, where the competitive set is larger and less settled, is the open question a $6.4 billion valuation is pricing as already answered.
Sources:
- Island Announces $400 Million Series F, Bringing Valuation to $6.4 Billion (Island press release)
- Island Announces $400 Million Series F, Bringing Valuation to $6.4 Billion (GlobeNewswire)
- Island raises $400 million at $6.4 billion valuation as AI agents reshape enterprise security (Calcalist)
- Island's $400M Series F and the AI agent security pivot (Runtime)
- Island Secures $250 Million as Valuation Continues to Soar to Nearly $5 Billion (Island press release, March 2025)
- Island Raises $175 Million in Series D Funding, Valuation Doubles to $3 Billion (Island press release, 2024)
- Cyera Acquires Oasis Security for $1B (TechCrunch)
Image credits
Hero: "Dallas (downtown), Texas, USA" by Zygmunt Put (Zetpe0202), via Wikimedia Commons, licensed under CC BY-SA 4.0. In-body image: "Dallas Skyline with Arts District at night" by Gattacal, via Wikimedia Commons, licensed under CC BY-SA 4.0. Both images depict Dallas, Texas, where Island is headquartered, and not Island's own offices.