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F5 agrees to buy Dublin-based CalypsoAI for $180m

CalypsoAI
/ 11th September 2025 /
George Morahan

Dublin-based CalypsoAI has agreed to a $180m (€153.3m) takeover by the Nasdaq-listed cubersecurity firm F5.

Seattle-headquartered F5 will acquire all issued and outstanding shares in CalypsoAI as part of the primarily cash-financed deal, which is expected to close later this month.

CalypsoAI has built a platform that offers real-time threat defence, cybersecurity exercises (red teaming) at scale, and data security to enterprises deploying generative and agentic AI.

Its capabilities will be integrated into F5's application delivery and security platform. F5 expects the deal to be immaterial to its revenue and operating results. The company reported revenue of $780m and income of $196m in its third quarter.

“AI is redefining enterprise architecture—and the attack surface companies must defend,” said François Locoh-Donou, president and chief executive of F5.

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“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.” 

Last October, Calypso announced Dublin as its global co-headquarters and said it would expand its workforce by 100.

The company was founded in Silicon Valley in 2018 and raised $23m in a Series A funding round from investors such as Paladin Capital Group, Lockheed Martin Ventures, Hakluyt Capital and Expeditions Fund in mid-2023.

The Series A round brought the total funding raised by CalypsoAI since launch to $38.2m.

Donnchadh Casey, chief executive of CalypsoAI, said: “Enterprises want to move fast with AI while reducing the risk of data leaks, unsafe outputs, or compliance failures.

“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.

CalypsoAI
CalypsoAI has agreed a $180m acquisition by F5.

"F5 and CalypsoAI are more than the sum of their parts: high performance application delivery and AI security that enable businesses to deliver innovation faster without increasing risk.” 

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

Pictured at the opening of CalypsoAI’s Global Co-Headquarters in October 2024 were (l-r) Kathleen Bohan (Vice President, Emerging Business Division, IDA Ireland), Jimmy White, (Chief Technology Officer, CalypsoAI), Peter Burke (Minister for Enterprise, Trade and Employment), Donnchadh Casey (Chief Executive Officer, CalypsoAI), Denis Curran (Head of Emerging Business, International Financial Services and Engineering, IDA Ireland). (Pic: File)

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