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 expected."
Bar Kogan said the size of the financing reflects investors' conviction that AI security will become one of cybersecurity's most important markets.
"The amount raised reflects investors' belief that this category will produce very large companies and become one of the most important areas in cybersecurity," he said. "Funds are willing to back companies they believe can become category leaders. Our goal is not to build a company to sell, but to build an independent, global company, and we have strong momentum."
He added that the rise of artificial intelligence is reshaping the cybersecurity industry.
"AI is reshuffling the cards across every industry, including cybersecurity. Every incumbent is vulnerable, and smaller companies have an opportunity to redefine the market," Bar Kogan said. "Our mission is to control AI. Trillions of dollars are being invested in AI, and the companies that help enterprises deploy it safely will be worth billions. Very few companies today can provide comprehensive control over AI agents."
Onyx's platform enables organizations to discover, manage, and govern AI agents, whether they are developed internally or sourced from third-party providers. The company's technology monitors every stage of an agent's reasoning process, allowing organizations to detect, prevent, and remediate malicious or unintended behavior before it causes damage.
Hila Zigman, General Partner at Cyberstarts, which led Onyx's Seed round, said the emergence of AI agents is creating an entirely new cybersecurity category.
"As AI agents become an integral part of critical enterprise workflows, organizations need to ensure they operate securely, consistently, and in accordance with corporate policies," Zigman said. "Onyx Security is building the control layer that will enable enterprises to adopt AI at scale. We believe this will become one of the most important cybersecurity categories of the coming decade."
