Rein Security Secures $25 Mn to Strengthen AI Agent Security

Rein Security was founded in 2024. It builds security technology that watches AI agents while they work across enterprise systems. Rein Security announced the funding on October 8 2026 as more businesses use AI agents to handle data, open applications and automate tasks.

Rein Securitys AI Security Platform

Rein Security offers real‑time monitoring and protection for AI agents that work inside enterprise environments. The platform uses sidecar technology to record the actions of agents the resources they use and the code that drives them.

The platform helps security teams spot behaviour, enforce controls and stop harmful actions before they damage systems. It also secures the AI agent supply chain without needing companies to route data through a gateway or proxy.

The need for this technology is rising as AI agents become more independent and gain access to business systems. Unlike software autonomous agents can act on instructions from other systems, which creates security risks that are hard to spot with normal methods.

How Rein Security Will Use the Funding

Rein Security will use the capital to speed up product development push research into agentic AI security and grow its global team.

Rein Security said its revenue grew eight times and its customer base grew five times after launching in January 2026.

Rein Security’s customers are in industries such as financial services, healthcare, retail, SaaS, data and energy. Rein Security said its platform already protects thousands of AI agents that together perform millions of actions.

Customers include Flex, Swimlane, Dun & Bradstreet and Lemonade. Rein Security says its technology protects AI agents that support Lemonade services for than three million active customers and agentic products used by over 240,000 Dun & Bradstreet customers.

Investors Back Rein Securitys Approach

Glilot Capital and Sienna Venture Capital co‑led the Series A round showing that investors are interested in security solutions made for enterprise AI systems.

Arik Kleinstein of Glilot Capital said that the growing ability of AI agents to access systems make decisions and act on their own is creating security needs for enterprises. He added that Rein Security can help shape this market.

Thomas Visan of Sienna Venture Capital said Rein Security’s platform tackles both new security threats that come with agentic AI.

The company has also earned recognition in the tech world. It was chosen for the AI Conference’s Start Up Showdown and named to TechCrunch’s Startup Battlefield 200 in the cybersecurity category.

About Rein Security

Rein Security is an AI security company that helps businesses watch manage and protect AI agents. Founded in 2024 Rein Security is co‑headquartered in New York City and Tel Aviv, Israel. The platform gives view of AI agent activity and uses real‑time controls to stop harmful actions, in enterprise environments.

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