Harmonic Security raises $50m Series B to govern workplace AI use

Harmonic Security raises $50m Series B to govern workplace AI use

14 October 2026: Harmonic Security, which sells software that watches and controls how employees use AI tools, has raised a $50 million Series B led by Crosspoint Capital Partners. Existing investors also took part, though the release does not name them. The company, which has offices in San Francisco and London, says total funding is now $76 million.

Not yet independently verified. The release reaches us through a Business Wire copy on Yahoo Finance; we did not find the same release on Harmonic's own site. Customer numbers are the company's claim, and its existing investors are not named. We will update this when it can be confirmed, and remove this note.

What the platform does

Harmonic calls its product a workforce AI security platform. According to the release, it classifies each AI task, works out why the employee is using it, and applies a control in real time rather than blocking the tool outright. It covers browser-based AI, desktop AI tools and agentic workflows.

Custom small language models read each interaction in context. A newer Usage Intelligence layer, the company says, shows which AI use cases create value, so that a security team can answer a business question as well as a risk one.

The release lists integrations and partners:

• Cisco Cloud Control's Agent Builder, connected through the Model Context Protocol;
• Claude's Compliance API;
• distribution partnerships with Climb and Distology.

Who uses it and how big it is

Harmonic says it protects and enables AI use for millions of employees at more than 100 companies, including some of the largest enterprises globally. It names none of them. The company says it has more than 90 people across the US and UK, and the new money will go into engineering and go-to-market teams in both countries.

This follows its $17.5 million Series A in October 2024, which the company announced on its own site.

What the investors and the chief executive say

Alastair Paterson, chief executive and co-founder, says in the release: "Every board I talk to is asking two questions: how do we reduce the risk of AI use, and are we getting value?"

Zach Sivertson, a managing director at Crosspoint Capital Partners, says: "Security has too often slowed the adoption of new technology."

Reading the claims

Everything about scale in this announcement comes from Harmonic: the number of employees covered, the number of companies and the headcount. The release does not give revenue, pricing, or a valuation, and it does not say how many of the 100 companies pay for the full platform rather than a subset of features. Buyers comparing workforce AI controls will want those answered in a trial rather than from a funding release.

Company profile on TrustList: Harmonic Security

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Sources

• Harmonic Security (via Business Wire): Harmonic Security raises $50 million Series B, 14 October 2026
• Harmonic Security: raises $17.5 million Series A (October 2024), 2 October 2024