Tessian

Tessian provides a cloud email security platform that intelligently protects organizations against advanced threats and inadvertent data loss. Leveraging artificial intelligence and machine learning, the platform builds individual behavioral models to proactively identify and prevent human-activated risks in email communications. Its approach focuses on securing the human layer, addressing vulnerabilities often overlooked by traditional perimeter defenses.

The company was founded in 2013 by Tim Sadler, Tom Adams, and Ed Bishop. Their core insight stemmed from recognizing that human error is a significant vector for cybersecurity incidents. This led them to develop a security solution designed to understand and mitigate the specific ways people interact with email, moving beyond rule-based systems.

Tessian's solutions serve various organizations seeking to safeguard their sensitive information and systems from evolving cyber threats. The company's long-term vision centers on enabling secure and productive work environments, ensuring that individuals can operate freely without inadvertently compromising their organization's security posture.

# High-Level Overview

Tessian is an AI-driven cybersecurity company specializing in "Human Layer Security"—protecting organizations against data breaches and security threats caused by employee error rather than malicious code.[1][2] Founded in 2013, the company builds a machine learning-powered email security platform that automatically prevents threats like misdirected emails, data exfiltration, accidental data loss, business email compromise, and phishing attacks without requiring rule-writing or disrupting employee workflows.[1][2]

Tessian serves enterprises across finance, law, technology, healthcare, and other regulated industries where sensitive data handling is critical.[4] The company operates on a subscription-based model and has achieved an estimated annual revenue of $75 million as of June 2025, demonstrating strong market traction.[3] In December 2023, Tessian was acquired by Proofpoint, integrating its specialized AI capabilities into Proofpoint's broader data loss prevention solutions.[3]

# Origin Story

Tessian was founded in 2013 by Tim Sadler, Ed Bishop, and Tom Adams, who initially launched the company under the name CheckRecipient to solve a specific problem: highly sensitive emails being sent to the wrong recipients.[4] The founders recognized an opportunity to disrupt traditional rule-based email security by applying machine learning to large datasets, enabling threat prevention without predefined rules or requiring behavioral changes from end users.[4]

The company gained early validation from top-tier venture capital investors, raising more than $17 million from firms including Sequoia, Accel, March Capital, and Balderton Capital.[4][5] This backing reflected investor confidence in the team's technical expertise—composed of mathematicians, engineers, and data scientists—and the market opportunity in human-centric cybersecurity.[4]

# Core Differentiators

• Automated threat prevention: Unlike legacy email security solutions that rely on manual rule-writing and investigation, Tessian's machine learning platform automatically detects and prevents threats at scale, including misdirected emails, misattached files, insider threats, and advanced phishing.[5]

• Minimal workflow disruption: The platform secures the human layer without creating friction for employees, allowing them to work efficiently while remaining protected.[1][2]

• Specialized focus: Tessian concentrates exclusively on human-layer security risks—an area often overlooked by traditional security methods—rather than attempting to be a generalist security vendor.[3]

• Proven ROI: Customer testimonials highlight rapid value realization, with some organizations seeing measurable returns within weeks of deployment and unprecedented visibility into inadvertent data loss incidents.[9]

• Compliance and certification: The platform holds BSI ISO 27001 certification and Cyber Essentials Plus accreditation, meeting stringent security and compliance standards.[9]

# Role in the Broader Tech Landscape

Tessian operates at the intersection of two powerful trends: the rising sophistication of cyberattacks targeting human behavior and the maturation of machine learning as a practical security tool. Research indicates that attacks exploiting human error account for more than 90% of successful cyberattacks, with 65% of data loss incidents resulting from misdirected emails alone.[7] This reality has exposed a critical gap in traditional security architectures, which focus primarily on perimeter defense and malware detection rather than human decision-making.

The company's emergence reflects a broader shift in cybersecurity from prevention-only models to human-centric risk management. As regulatory requirements tighten and data breaches become increasingly costly, organizations recognize that technical controls alone are insufficient—they must also address the behavioral and procedural vulnerabilities that employees inadvertently create. Tessian's acquisition by Proofpoint signals the consolidation of this specialized capability into larger security platforms, validating the strategic importance of human-layer security within the broader cybersecurity ecosystem.

# Quick Take & Future Outlook

Tessian's integration into Proofpoint positions the technology to reach a significantly broader customer base while maintaining its specialized focus on human-layer threats. The company's core insight—that machine learning can prevent employee-caused security incidents without creating security theater or workflow friction—remains highly relevant as organizations grapple with the human dimension of cybersecurity.

Looking forward, the trajectory of human-layer security will likely be shaped by three factors: the increasing sophistication of social engineering attacks, regulatory mandates requiring demonstrable controls over data handling, and the maturation of AI models capable of understanding organizational context and communication patterns. Tessian's technology, now embedded within Proofpoint's platform, is well-positioned to evolve alongside these trends. The company's future influence will depend on how effectively it scales its machine learning models to detect emerging threat patterns and how well it integrates with the broader security operations workflows that enterprises rely on. In a landscape where 90% of breaches involve human error, solving this problem at scale remains one of cybersecurity's most valuable opportunities.