Harmonic Security raises USD $50 million in Series B

Harmonic Security has raised USD $50 million in a Series B funding round led by Crosspoint Capital Partners, bringing its total funding to USD $76 million.

The new investment will support expansion of the company's engineering and commercial teams in the United States and the United Kingdom. Harmonic Security has more than 90 employees across the two markets.

Harmonic Security sells software designed to help companies oversee how employees use artificial intelligence tools at work. Its platform is used by more than 100 companies and covers browser-based AI tools, desktop AI applications and agentic workflows.

The business has signed new distribution partnerships with Climb and Distology as it broadens its route to market. It has also expanded integrations with other technology platforms used by corporate customers.

Its product is built around small language models that analyse individual AI interactions in context. According to Harmonic Security, that approach lets customers distinguish between different types of activity, such as a developer referencing a schema and a user entering live credentials.

The company also offers what it calls a usage intelligence layer, designed to help business and security leaders track how AI tools are being used across organisations. Harmonic Security says this is intended to show which use cases are proving useful and where further investment may be warranted.

Alastair Paterson, Chief Executive Officer and Co-Founder of Harmonic Security, said the company is trying to answer two questions that senior corporate leaders are increasingly asking about workplace AI.

"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," said Alastair Paterson, Chief Executive Officer and Co-Founder of Harmonic Security.

"From the very start, we doubled down on our custom small language models, which means we can benefit from a unique insight into enterprise AI use," Paterson said.

Platform reach

Harmonic Security's reach has also increased through integrations with larger technology ecosystems. It is listed among ecosystem integrations for Cisco Cloud Control's Agent Builder through Model Context Protocol.

The company has also built an integration with Claude's Compliance API. This gives security teams visibility into Claude Platform activity logs and, for organisations using Claude Enterprise on Anthropic-hosted deployments, access to conversation content.

Crosspoint Capital said the investment reflects demand from organisations seeking tighter oversight of AI adoption without blocking employees from using new tools. The funding round was oversubscribed.

"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. Harmonic gives leaders the visibility and confidence to accelerate adoption, while empowering employees to use the tools that make them more productive, all with the right guardrails in place. We're proud to partner with Alastair and the Harmonic team," said Zach Sivertson, Managing Director of Crosspoint Capital Partners.

The latest round comes as companies face growing pressure to manage employees' use of generative AI systems, particularly where personal accounts, sensitive data exposure and unapproved workflows create oversight problems. Harmonic Security says its platform is intended to close those gaps by applying controls in real time.

Paterson said the funding would allow the company to move faster as the market develops.

"We've got some real momentum, and I know we're just getting started. This round means we get to build that out faster and continue rapidly responding to the AI landscape shifts," Paterson said.