Dallas-based browser security startup Island announced Thursday it has raised $400 million in funding, bringing its valuation to $6.4 billion. CEO Mike Fey stated that AI attacks are driving demand for new security tools because "all the old controls are failing." The funding round was led by Evolution Equity Partners. Island plans to use the capital for research and development and to expand into new markets such as Europe, Asia, and the Middle East, with an anticipated increase in its workforce from 1,000 to 1,500 employees by mid-next year. Island's clients include Pfizer, Chipotle, and American Airlines.