Harmonic Security Raises $50M Series B to Expand US and UK Teams

Harmonic Security announced on October 14, 2026, that it raised a $50 million Series B round led by Crosspoint Capital Partners, with participation from existing investors. The company said the round, which it described as oversubscribed, brings its total funding to $76 million.

Series B Round and Expansion Plans

In the funding announcement, datelined San Francisco and London, Harmonic said it will use the new capital to expand its engineering and go-to-market teams in the United States and the United Kingdom. The company said it has grown to more than 90 people across the two countries.

Harmonic said it protects and enables AI use for millions of employees at more than 100 companies, including what it describes as some of the largest enterprises in the world. The company also signed new distribution partnerships with Climb and Distology.

“Security has too often slowed the adoption of new technology. As organizations embrace AI, they shouldn’t have to choose between moving quickly and maintaining control,” said Zach Sivertson, managing director at Crosspoint Capital Partners. He said Harmonic gives leaders the visibility and confidence to accelerate AI adoption while employees use the tools that make them more productive, with the right guardrails in place.

Alastair Paterson, Harmonic’s chief executive and co-founder, said the company has real momentum and is just getting started, adding that the round allows it to build faster while continuing to respond to shifts in the AI landscape.

Platform Capabilities and Ecosystem Integrations

Harmonic describes its product as the only platform that classifies every AI task, discovers why it is used, and then controls it in real time. The company said that in the 12 months before the announcement it extended beyond browser-based AI monitoring to cover desktop AI tools and agentic workflows in a single platform, coverage it frames as closing the gap where personal-account use, sensitive data exposure, and other risks tend to start.

The platform is built on custom small language models that, according to the company, read each AI interaction in context and return a result in milliseconds, enough to distinguish a developer referencing a schema from someone pasting live credentials. Harmonic said the same engine powers its Usage Intelligence layer, which shows leaders which AI use cases are creating value, which employees have found a faster way to work, and where to invest next rather than where to clamp down.

“Every board I talk to is asking two questions: how do we reduce the risk of AI use, and are we getting value? Most vendors struggle to answer the first, yet we address both,” Paterson said. He said the company committed to its custom small language models from the start, which he said gives it unique insight into enterprise AI use.

Harmonic is named among the ecosystem integrations for Cisco Cloud Control’s new Agent Builder, announced at Cisco Live, connecting through the Model Context Protocol. Separately, the company built an integration with Claude’s Compliance API, which Harmonic said gives security teams visibility into Claude Platform activity logs and, for organizations on Claude Enterprise, into conversation content across Anthropic-hosted deployments.

Company History and Prior Funding

Harmonic Security was founded in August 2023, according to the company’s About page. Paterson is chief executive and co-founder, and Bryan Woolgar-O’Neil is chief technology officer and co-founder. Ten Eleven Ventures led the company’s $7 million seed round in October 2023, the month the company launched.

The company was named an RSA Innovation Sandbox finalist in April 2024 and launched its Harmonic Protect data protection product in July 2024. On October 2, 2024, Harmonic announced a $17.5 million Series A round led by Next47, with Next47 general partner T.J. Rylander joining the board. Harmonic said at the time that it had secured more than $26 million since launch, that enterprise customers were already in double figures, and that its data protection product was in active use by thousands of employees. The company employed 30 people across the United States and the United Kingdom at the time.

The About page lists the company’s board and investors as Rylander, Bain Capital CISO Mark Sutton, Ten Eleven Ventures founder Alex Doll, In-Q-Tel partner Grant Whiting, and N47’s Colton Dempsey, along with advisor René Bonvanie, CMO emeritus of Palo Alto Networks.

Harmonic launched its MCP Gateway in October 2025 and introduced an updated brand in January 2026.