F5 Networks Acquires AI Security Firm CalypsoAI For $180 Million

Key takeaways

Seattle-based application delivery and security company F5 Networks announced Thursday its intention to acquire CalypsoAI, an Irish-American AI security startup, for $180 million in cash. The acquisition highlights the mounting cybersecurity challenges enterprises face as they rapidly integrate artificial intelligence into their business operations.

Strategic response to growing AI security threats

The deal comes at a time when companies across industries are rushing to deploy generative AI systems while grappling with new categories of cybersecurity threats that traditional security tools struggle to address. CalypsoAI, founded in 2018 with operations in Dublin and New York, specializes in protecting AI systems against emerging attack methods, including prompt injection and jailbreak attacks.

"AI is redefining enterprise architecture—and the attack surface companies must defend," said François Locoh-Donou, President and CEO of F5. "Traditional firewalls and point solutions can't keep up. The addition of CalypsoAI will give enterprises the confidence to innovate faster and better protect critical data as they rely on F5 to deliver and secure apps, APIs, and AI models across their environment."

CalypsoAI's unique technology approach

CalypsoAI addresses the security challenges through what the company calls "model-agnostic" security, providing protection regardless of which AI models or cloud providers enterprises use. The platform conducts automated red-team testing against thousands of attack scenarios monthly, generating risk assessments and implementing real-time guardrails to prevent data leakage and policy violations.

"Enterprises want to move fast with AI while reducing the risk of data leaks, unsafe outputs, or compliance failures," said Donnchadh Casey, CEO of CalypsoAI. "Our customers rely on us to pressure test AI systems at scale, set inference layer guardrails that adapt as models change, and to gain visibility and auditability across their AI estate."

The company's approach focuses on the inference layer where AI models process requests, rather than securing the models themselves. This strategy enables real-time threat defense and creates what CalypsoAI calls an "Inference Perimeter" that protects across models, vendors, and environments.

Transaction details and market context

F5 will acquire all issued and outstanding shares of CalypsoAI for $180 million in purchase consideration financed primarily with cash. The transaction is expected to be immaterial to F5's revenue and operating results and is subject to customary closing conditions, expected to close in F5's fourth quarter fiscal year 2025, ending September 30, 2025.

The acquisition is part of a broader trend in the cybersecurity industry, with established companies racing to add AI-powered security offerings to their portfolios. F5 has been particularly active in strategic acquisitions this year, having purchased San Francisco-based Fletch in June and observability firm MantisNet in August.

CalypsoAI has raised over $40 million in venture funding from investors including Paladin Capital Group, Lockheed Martin Ventures, and Hakluyt Capital. The company was a top-two finalist in the 2025 RSAC Innovation Sandbox contest and named one of Fast Company's Most Innovative Companies in AI for 2025.

Foros Advisors LLC acted as financial advisor to F5 while Sullivan & Cromwell LLP acted as legal advisor. Cooley LLP provided legal counsel to CalypsoAI.

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