What Does Tessian Do?

Total employees53
HeadquartersLondon
Founded2013

Tessian is a cybersecurity company that pioneered Human Layer Security. It leverages machine learning to understand human behavior and protect enterprises from threats initiated by people, such as spear phishing, accidental data loss via misdirected emails or misattached files, and insider threats. Acquired by Proofpoint in late 2023, Tessian's technology aims to automatically prevent security incidents by securing the human layer, turning employees from a potential vulnerability into a strong line of defense.

Where Is Tessian's Headquarters?

Tessian officeTessian officeTessian officeTessian office
*Images sourced via web search. Rights belong to original owners

HQ Function

Serves as a key operational hub, historically housing leadership, engineering, product development, and core business functions. Post-acquisition by Proofpoint, it continues to be a center for Human Layer Security innovation and talent.

Notable Features:

Located in the redeveloped 3 Finsbury Avenue building within the Broadgate campus, a major business and tech hub. The office likely features modern, agile workspaces designed for collaboration and technological innovation, with access to campus amenities.

Work Culture:

Tessian historically cultivated a dynamic and mission-driven work culture focused on innovation in cybersecurity. The London HQ embodied a collaborative, fast-paced environment encouraging continuous learning and problem-solving, typical of successful tech scale-ups in the competitive London ecosystem. This ethos is expected to integrate into Proofpoint's culture.

HQ Significance:

As the founding city and primary operational center before its acquisition, the London headquarters was crucial for Tessian's strategic direction, product innovation, and access to a rich talent pool. It remains a key site for Proofpoint's Human Layer Security initiatives.

Values Reflected in HQ: The choice of a modern, well-connected location in a tech hub reflects Tessian's (and now Proofpoint's) commitment to innovation, collaboration, and attracting top talent. The focus on an open and dynamic environment mirrors the approach to solving complex cybersecurity challenges.

Location:

Prior to its acquisition by Proofpoint, Tessian established a global presence with key offices in London (UK), Austin (USA), and Boston (USA). These locations supported global operations including sales, marketing, customer support, and product development. As part of Proofpoint, Tessian's technology and expertise are now leveraged across Proofpoint's extensive global footprint, serving customers worldwide.

Street Address:

3 Finsbury Avenue

City:

London

State/Province:

England

Country:

United Kingdom

Where Else Does Tessian Operate Around the World?

Austin, Texas, USA

Address: 801 Barton Springs Rd, Austin, TX 78704, USA

To expand reach in North America, provide localized support for US clients, and tap into Austin's burgeoning tech talent pool.

Boston, Massachusetts, USA

Address: 24 School St, Boston, MA 02108, USA

To strengthen East Coast presence, engage with a diverse range of clients, and access specialized talent in the region for Human Layer Security solutions.

Buying Intent Signals for Tessian

Highperformr Signals uncover buying intent and give you clear insights to target the right accounts at the right time — helping your sales, marketing, and GTM teams close more deals, faster.

Notable news
Hiring actively
Corporate Finance
Corporate Finance
Corporate Finance
Corporate Finance
Corporate Finance
*Example signal, not calculated in real time

Who's Leading Tessian? Meet the Executive Team

As of April 2025, Tessian' leadership includes:

Tim Sadler - Co-founder & CEO (Transitioned to Advisor at Proofpoint)
Ed Bishop - Co-founder & CTO (Transitioned to VP, Human Layer Security at Proofpoint)
Tom Adams - Co-founder (Transitioned to Advisor at Proofpoint)
Josh Yavor - CISO (at time of acquisition)
Sabrina Castiglione - Chief Operating Officer (at time of acquisition)
Allen Lieberman - Chief Product Officer (at time of acquisition)
Kevin Resch - Chief Financial Officer (at time of acquisition)

Who's Investing in Tessian?

Tessian has been backed by several prominent investors over the years, including:

Sequoia Capital
Accel
Balderton Capital
Latitude Ventures
March Capital
Citi Ventures
Sozo Ventures
Operator Collective

What Leadership Changes Has Tessian Seen Recently?

Hire0
Exits3

The most significant executive changes at Tessian in the last 12 months (May 2023 - May 2024) revolve around its acquisition by Proofpoint, finalized in December 2023. This led to transitions for key leadership figures as Tessian integrated into Proofpoint. Standalone executive hires or departures unrelated to the acquisition were minimal during this period.

Departures

Tim Sadler, Departed role as CEO of Tessian following the company's acquisition by Proofpoint; became an Advisor.
Ed Bishop, Departed role as CTO of Tessian following the company's acquisition by Proofpoint; became VP, Human Layer Security at Proofpoint.
Tom Adams, Departed active operational C-level role at Tessian following the company's acquisition by Proofpoint; became an Advisor.

New Appointments:

Ed Bishop, Appointed to VP, Human Layer Security at Proofpoint, leading the integration and advancement of Tessian's technology within Proofpoint's portfolio.

What Technology (Tech Stack) Is Used byTessian?

Discover the tools Tessian uses. Highperformr reveals the technologies powering your target accounts — helping your sales, marketing, and GTM teams prioritize smarter and close faster.

Tessian Email Formats and Examples

Tessian, prior to its acquisition by Proofpoint, commonly utilized email formats typical for tech companies. The most prevalent format was `first.last@tessian.com`. While employees are now part of Proofpoint, historical contact information might follow this pattern.

first.last@tessian.com

Format

jane.doe@tessian.com

Example

85%

Success rate

What's the Latest News About Tessian?

Proofpoint NewsroomDecember 29, 2023

Tessian news title: Proofpoint Completes Acquisition of Tessian

Proofpoint, Inc., a leading cybersecurity and compliance company, announced it has completed its acquisition of Tessian. This strategic acquisition brings together Tessian's advanced AI-powered defense against accidental data loss and sophisticated email threats with Proofpoint's comprehensive threat protection platform....more

Tessian BlogNovember 1, 2023

Tessian news title: Tessian is Joining Forces with Proofpoint to Secure the Human Layer

Tessian announced its agreement to be acquired by Proofpoint. The company highlighted the shared vision of securing the human element in cybersecurity and expressed excitement about accelerating its mission to protect enterprises from human-activated risk on a larger scale as part of Proofpoint....more

Tessian BlogMay 16, 2023

Tessian news title: Making it easier to stop data loss from misdirected emails and misattached files

Tessian announced enhancements to its Human Layer Security platform designed to more effectively prevent data loss from misdirected emails and misattached files. The updates aimed to improve the user experience and strengthen defenses against common forms of human error leading to data breaches....more

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