Rein Security Raises $25M to Secure the AI Agents Enterprises Build and Stop the Ones That Attack Them
aiinsider ·
Rein Security has secured $25 million in Series A financing to expand its AI-native runtime security platform for enterprises. The round was co-led by Glilot Capital and Sienna Venture Capital, bringing the company's total funding to $35 million. Rein’s patented sidecar technology provides real-time visibility into every line of code executed by AI agents, allowing security teams to block harmful actions without using traditional gateways or proxies. Since launching in January 2026, the company has increased revenue eightfold and grown its customer base fivefold, serving major clients such as Dun & Bradstreet and Lemonade. The funding will support product development, agentic research, and global hiring as enterprises face rising risks from autonomous AI agents and adversarial attacks. Industry data indicates that the market for securing AI is projected to grow significantly, reaching nearly $4.8 billion by 2027. Rein addresses both the protection of internal agents and defense against external AI-driven threats through proactive prevention strategies.
aiinsider