AI security startup Onyx raises $113 million Series B at $640 million valuation

Israeli cybersecurity startup Onyx Security has raised $113 million in Series B funding, led by Bessemer Venture Partners, just four months after emerging from stealth with $40 million. The round values the company at an estimated $640 million, marking a significant increase in valuation.

Founded in 2024 by Maxim Bar Kogan and Gil Elbaz, Onyx develops a platform that helps enterprises secure, manage, and govern AI agents by controlling permissions, monitoring activity, and detecting potentially harmful or unintended behavior.

The new funding will accelerate development of Onyx’s AI models and support expansion of its sales and marketing operations in the U.S. and other international markets. The company has more than 80 employees across Israel, the U.S., and Canada and already serves several Fortune 500 customers.

Onyx is positioning itself in the growing AI security market, as businesses increasingly adopt autonomous AI agents for critical workflows.

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