From AI Insider · James Dargan · · 1m 40s
Rein Security Raises $25M for AI Agent Security
Rein Security secures $25M to protect AI agents from attacks as enterprises deploy more autonomous systems.
In brief
Rein Security secures $25M to protect AI agents from attacks as enterprises deploy more autonomous systems. Rein Security raised $25 million in Series A funding to secure AI agents against attacks, with 8x revenue growth since 2026 launch. Originally reported by AI Insider.
Rein Security Raises $25M
Rein Security, an AI-native runtime security platform for enterprises, has secured $25 million in Series A financing co-led by Glilot Capital and Sienna Venture Capital.
Total Funding $35M
The round brings Rein Security’s total funding to $35 million with participation from Corner Ventures, Atlacle and RNP Capital Advisors.
Patented Sidecar Technology
Rein’s platform uses patented sidecar technology that operates where AI agents execute actions to provide real-time visibility and guardrails.
8x Revenue Growth
Since its January 2026 launch, Rein has grown revenue 8x and its customer base 5x.
Key Customers
Rein secures AI agents for Dun & Bradstreet and Lemonade, supporting over three million customers and 240,000 users.
Security Challenges
Enterprises face two security challenges: securing agents they build while defending against increasingly capable AI-driven attacks.
Gartner Projections
Gartner projects the ai security market to reach $4.8 billion in 2027, up 68.7% from 2026, and $7.7 billion by 2028.
Real-World Threats
Rein detected a prompt injection attack that redirected an agent outside its intended role before causing damage.
Investor Support
Glilot Capital and Sienna Venture Capital back Rein’s platform as the solution for the growing agent economy.
Funding Use
Rein will use the $25 million for product development, agentic research and global hiring.
Security Impact
Rein’s platform blocks harmful actions without routing data through gateways or proxies, securing agent supply chains.
What matters most
Rein Security raised $25 million in Series A funding to secure AI agents against attacks, with 8x revenue growth since 2026 launch.
