Onyx Security raises $113 million in Series B funding, four months after launching publicly, to help companies securely manage AI agents; The cybersecurity startup has now raised $153 million from investors including Bessemer Venture Partners and Cyberstarts Related TopicsCybersecurity startup Onyx Security has raised $113 million in a new investment round led by Bessemer Venture Partners, with additional investment from Cyberstarts, TCV, Conviction, FirstMark, Vintage Investment Partners, QuantumLight and G Squared. The company has now raised $153 million in total.GalleryGil Elbaz and Maxim Bar Kogan, Onyx Security founders (Photo: Netanel Tobias)The company develops security tools that help organizations use AI agents — software systems that can perform tasks independently — while keeping control over what those systems can access and do. Its platform helps companies manage permissions, track AI activity and identify potential risks as they introduce AI into their operations.Onyx said the new funding will support the development of its AI technology and expansion into the United States and other markets.The company was founded in 2024 by Maxim Bar Kogan, a former Unit 8200 officer and former VP of Product and Engineering at Mixtiles, together with Gil Elbaz, an AI entrepreneur who previously served in the Israeli Air Force’s operational technology unit.Today, Onyx employs more than 80 people across Israel, the United States and Canada and works with several Fortune 500 companies. In June, Anthropic announced that it had integrated Onyx’s technology to help businesses adopt AI more securely.Gil Elbaz, co-founder Onyx Security (Photo: Courtesy )As companies increasingly use AI agents for tasks that were previously handled by employees or traditional software, Onyx aims to provide a way to monitor and control those systems. Its platform can track AI agents’ actions, detect suspicious or unintended behavior and step in when needed to prevent harmful activity.“In 2025, less than one percent of all actions were performed by AI agents,” said Maxim Bar Kogan, CEO and co-founder of Onyx Security. “In the near future, these autonomous systems will be responsible for the majority of digital actions. The key question is how organizations can ensure that every action is legitimate.”Hila Zigman, managing partner at Cyberstarts, which led Onyx’s seed investment, said: “As AI agents become part of critical business processes, organizations need confidence that these systems operate safely and according to company policies. Onyx is building the tools that will help companies adopt AI more widely while maintaining control.”Onyx Security builds technology that helps companies securely use and manage AI agents. Its platform allows organizations to identify AI systems in use, set rules for how they operate and monitor their activity. The company’s AI models and Onyx Guardian Agent continuously track AI behavior and can intervene when they detect unsafe or unusual actions.Comments