Island raises $400M at a $6.4B valuation

Island announced a $400 million Series F that values the enterprise-browser security company at $6.4 billion, more than doubling its valuation since 2024, according to the company’s funding announcement. Island says it now employs 1,000 people and is extending its control plane across identity, access, data, networks and audit trails for human and AI-agent work. Builders should treat the round as a market signal—not proof that one control plane makes agents safe—and compare its promises with AISI’s 8.2% out-of-scope evaluation rate before buying the category.