Harmonic Security Raises $50M Series B to Secure Enterprise AI Use

Harmonic Security has raised $50 million in Series B funding to help businesses manage the security risks associated with employees using artificial intelligence tools. The round was led by Crosspoint Capital Partners, with participation from existing investors whose identities were not disclosed. The funding brings the company's total capital raised to $76 million.

Founded in October 2023, Harmonic Security develops software that monitors how employees interact with AI applications and applies real-time security controls. Rather than blocking AI adoption entirely, the company aims to help organizations understand which tools employees use, what information they share and how AI contributes to workplace productivity.

The company was co-founded by Alastair Paterson and Bryan Woolgar-O'Neil, both of whom previously worked at cybersecurity company Digital Shadows. Paterson led Digital Shadows before its acquisition by ReliaQuest for $160 million in 2022.

Harmonic plans to use its new funding to expand engineering, sales and marketing across the United States and the United Kingdom.

Harmonic Security's $50M Series B Funding

Crosspoint Capital Partners led the $50 million Series B round as enterprise security providers face increasing pressure to address risks associated with generative AI and AI agents.

According to Tech Funding News, the round was oversubscribed. However, Harmonic did not disclose its valuation or identify the existing investors who participated.

The company's earlier financing rounds included:

• Seed funding: $7 million led by Ten Eleven Ventures in 2023.

• Series A: $17.5 million led by Next47 in October 2024.

• Series B: $50 million led by Crosspoint Capital Partners in October 2026.

• Total funding: $76 million.

The new investment comes as businesses increasingly adopt AI tools while trying to maintain control over sensitive data, employee activity and access to enterprise systems.

For Harmonic, the opportunity is to help organizations establish practical security controls without forcing employees to abandon AI tools that may improve their productivity.

From Digital Shadows to Harmonic Security

Harmonic's founding team brings experience from the cybersecurity industry.

CEO and co-founder Alastair Paterson previously co-founded Digital Shadows, a threat-intelligence company that helped organizations identify and manage digital risks. ReliaQuest acquired Digital Shadows in 2022 in a transaction valued at $160 million.

Harmonic's other co-founder, Bryan Woolgar-O'Neil, previously served as chief technology officer at Digital Shadows. The new company's data and machine learning team also includes people who worked at the earlier business.

Harmonic was established in October 2023 following consultations with more than 50 security leaders. The company says those discussions helped shape its approach to enterprise AI security.

The founding thesis is that organizations need visibility into AI usage rather than relying exclusively on restrictive policies. Employees may adopt new AI applications independently, creating potential exposure when sensitive information is shared without appropriate controls.

Harmonic's product is designed to give security teams a clearer picture of these interactions and apply controls while employees continue using AI tools.

How Harmonic Security Monitors Employee AI Usage

Harmonic's software monitors interactions with AI tools and applies security controls in real time. The company focuses on understanding the context of an interaction rather than simply flagging keywords or blocking an entire application.

According to Harmonic, its small language models analyze interactions within milliseconds. This allows the platform to distinguish between different situations that may appear similar at first glance.

For example, a developer discussing a database schema may be performing a legitimate technical task, while someone copying live credentials into an AI application could create a security risk. Understanding that distinction can help security teams apply more targeted controls.

The platform also includes a Usage Intelligence layer designed to help organizations understand how employees use AI and identify valuable applications.

This information can help management evaluate where AI is being adopted, assess potential exposure and make decisions about future AI investments.

Harmonic CEO Alastair Paterson said that business leaders increasingly want answers to two questions: how to reduce the risks associated with AI use and whether their organizations are receiving value from AI investments.

The company's strategy is to address both concerns through monitoring, security controls and visibility into employee usage.

These capabilities are particularly relevant as companies move from experimentation with standalone AI assistants toward broader deployments involving enterprise data, connected applications and AI agents.

Customer Growth and Expansion Plans

Harmonic reports that its software is used by millions of employees across more than 100 companies, including large enterprises.

According to SecurityBrief UK, the company acquired approximately 100 customers during 2026 and reached its annual customer target in September. The report does not provide a detailed breakdown of customer sizes, revenue or retention.

The company has also expanded its workforce substantially. Its team grew from approximately 30 people in October 2024 to more than 90 employees across the United States and the United Kingdom.

The latest funding will support further investment in engineering, sales and marketing across both regions.

Engineering expansion could help the company develop additional security capabilities as enterprise AI usage evolves. Sales and marketing investment will be important as Harmonic competes for customers that may already purchase cybersecurity products from established vendors.

The company has not disclosed its valuation or provided a detailed revenue forecast alongside the Series B announcement.

AI Security Competition Is Intensifying

Harmonic is entering a market where cybersecurity companies are increasingly incorporating AI security into broader enterprise protection platforms.

The competitive landscape is also changing through acquisitions. According to the supplied report, SentinelOne acquired Prompt Security in a transaction that Calcalist estimated at approximately $250 million. Prompt Security had previously raised $23 million.

Cato Networks has also agreed to acquire Aim Security, with the transaction reportedly estimated at $300 million to $350 million.

These transactions suggest that established cybersecurity providers see strategic value in technologies designed to manage enterprise AI risks. Acquisitions can provide larger security platforms with specialized technology, existing customers and teams experienced in AI security.

Harmonic's approach centers on observing how employees use AI applications and applying controls at the point of interaction. The company is also expanding its coverage of AI agents, which can introduce additional risks when they have access to enterprise credentials or connected business systems.

Its challenge will be to demonstrate that its specialized approach offers enough value for organizations to purchase a separate product rather than relying on AI security features integrated into their existing cybersecurity platforms.

The Broader Enterprise AI Security Opportunity

As organizations introduce AI tools into daily operations, security teams must balance employee productivity with the protection of confidential information and business systems.

Traditional security policies may not fully address the variety of AI applications employees can access. Meanwhile, banning these tools outright may limit opportunities to automate work and improve efficiency.

Harmonic is targeting this gap with software intended to make AI usage more visible and manageable.

The supplied article cites a Gartner forecast projecting that the security software sector, including AI security, could grow from $15.6 billion in 2025 to $37.6 billion by 2030, representing an annual growth rate of 18.5%. These figures are the forecast reported in the source, rather than independently verified market outcomes.

The opportunity extends beyond monitoring conventional chatbots. As AI agents become more connected to enterprise applications, organizations may need stronger oversight of the information those agents access, the actions they perform and the credentials they use.

Harmonic's expansion into agent-related security reflects this changing environment. However, the company will need to keep pace with evolving enterprise requirements and competition from established vendors.

Will Harmonic Security Remain Independent?

Harmonic's latest funding round raises a broader strategic question about the future of specialized AI security companies.

Some competitors have been acquired by larger cybersecurity providers, creating potential paths to scale through integration with established products and distribution networks.

Harmonic, by contrast, has secured additional capital to continue building its own platform. Its experienced founding team, reported customer base and $76 million in total funding give it resources to pursue further growth, although none of these factors guarantees long-term independence.

One key question is whether businesses will continue buying dedicated AI security products or increasingly expect these capabilities to come bundled with their existing security software.

Another is whether specialized providers can maintain an advantage as major technology and cybersecurity companies expand their own AI monitoring and compliance offerings.

For Harmonic, the next stage will involve converting its reported customer traction into sustainable growth while demonstrating that its real-time controls and usage intelligence solve problems that existing platforms cannot adequately address.

Key Takeaways

• Funding: $50 million Series B.

• Lead investor: Crosspoint Capital Partners.

• Total funding: $76 million.

• Founders: Alastair Paterson and Bryan Woolgar-O'Neil.

• Founded: October 2023.

• Headquarters: San Francisco and London.

• Product: Real-time monitoring and security controls for employee AI usage.

• Reported reach: Millions of employees across more than 100 companies.

• Team: More than 90 employees across the US and UK.

• Use of funds: Engineering, sales and marketing expansion.

Harmonic Security's Series B highlights a growing enterprise challenge: enabling employees to use AI while keeping sensitive data and business systems protected. The company is betting that organizations need more than blanket restrictions. They need visibility, context-aware controls and a way to understand how AI is being used across the workplace.

Its next challenge is to prove that this specialized approach can compete with security capabilities increasingly offered by larger platforms.