AI security startup Onyx raises $113 million Series B at $640 million valuation Just four months after emerging from stealth, the Israeli startup is betting that securing AI agents will become one of cybersecurity's biggest markets. Cybersecurity startup Onyx Security has raised $113 million in a Series B funding round led by Bessemer Venture Partners, just four months after emerging from stealth with $40 million in funding, a $5 million Seed round and a $35 million Series A. The latest financing values the company at an estimated $640 million, representing a several-fold increase from its previous valuation. Onyx develops a platform that enables enterprises to deploy AI agents securely and at scale by managing permissions, monitoring agent activity, and preventing risks associated with autonomous AI systems. The new funding will be used to accelerate development of the company's next-generation AI models and expand its sales, business development, and marketing operations in the United States and other international markets. Founded in 2024 by Maxim Bar Kogan, a veteran of Unit 8200 and former Vice President of Product and Engineering at Mixtiles, and Gil Elbaz, an AI entrepreneur who previously served in the Israeli Air Force's Operational Technology Unit, Onyx now employs more than 80 people across Israel, the United States, and Canada. The company already works with several Fortune 500 customers. In June, Anthropic announced that it had integrated Onyx's technology to help enterprise customers adopt AI securely. Speaking with Calcalist, co-founder and CEO Maxim Bar Kogan said the company's rapid growth after emerging from stealth fueled investor interest. "Coming out of stealth marked the point at which we could begin selling broadly," he said. "Demand exceeded our expectations, we reached our targets very quickly, and that created tremendous investor interest and allowed us to raise this round much sooner than