Mimecast Leadership Team | Mimecast

Marc van Zadelhoff

Chief Executive Officer

Marc van Zadelhoff joined Mimecast as the company's second CEO and member of the board in January 2024, where he will lead all aspects of the business and guide the company as it enters its third decade of operation.

He is an accomplished executive with 25 years of experience in the cybersecurity industry. Prior to joining Mimecast, Marc was the CEO of Devo Technology, a cloud-based logging platform that he led through an intense growth phase where they raised $350M and tripled revenues. He also spent time as COO at LogMeIn, and was GM /CEO of IBM Security, an IBM Business Unit that he co-founded. Under his leadership, IBM Security grew to 8,000 employees and $2.5 billion in revenue.

Marc is a curious and committed leader that puts Mimecast’s 2,200+ employees first and works alongside them to ensure customer organizations can secure human risk. He was born in the Netherlands and currently resides in the Boston-area with his wife and three daughters. He holds an MBA from The Wharton School of the University of Pennsylvania and obtained a B.A. from Bowdoin College.

Ranjan Singh

Chief Product & Technology Officer

Ranjan Singh joined Mimecast as the Chief Product & Technology Officer in April 2025, bringing over two decades of experience driving product innovation and delivering exceptional customer-focused solutions. In his role, Ranjan leads the Product and Engineering organizations, as they continue delivering technology that empowers organizations to secure human risk.

Before joining Mimecast, Ranjan spent more than three years as a senior leader at Kaseya where he was instrumental in shaping its success, overseeing a global team of 1,200+ employees and managing a portfolio of over 40 SaaS products, contributing to $1.5 billion in revenue.

Known for his expertise in integrating products across multiple acquisitions and building multi-product platforms, as well as a customer-centric mindset and meticulous attention to detail, Ranjan’s leadership has consistently driven growth, operational excellence, and customer satisfaction.

Prior to Kaseya, Ranjan held key product leadership roles at Crestron Electronics and IPC Systems, where he led technology integration, product development, and strategic execution.

Ranjan earned his undergraduate degree from Victoria University in Melbourne, Australia, and completed his master’s degree at New York University. Born in India, and having lived in Australia, and the United States, he is well-versed in navigating international markets and leading teams across cultures. When not driving innovation at Mimecast, Ranjan enjoys spending time with his wife and two children in their hometown in Northern New Jersey.

Adenike (Nikki) Cosgrove

Chief Marketing Officer

Adenike Cosgrove joined Mimecast in November 2024 as Chief Marketing Officer. Adenike Cosgrove leads Mimecast’s global marketing organization, driving strategic growth and positioning for the company in new and existing markets. Adenike is an accomplished technology executive with expertise across the spectrum of product and business strategy including human risk management, data privacy and compliance. Adenike has close to 20 years’ experience in the cybersecurity industry.

Prior to joining Mimecast, Adenike spent nine years at Proofpoint, serving as marketing leader in EMEA, following the company’s acquisition of Return Path Email Fraud Protection, where she led product marketing and served as Vice Chair of the DMARC.org working group. Earlier in her career, Adenike worked as lead EMEA advisor to security and risk professionals for Forrester Research and Canalys, where she developed a deep understanding of CISO challenges and helped clients with their information and cybersecurity strategies.

Adenike holds a Bachelor of Engineering degree from the University of Hull and a Master of Research, Telecommunications, from University College London. She has lived in Japan, Hong Kong and Nigeria, and currently resides in London.

David Call

Chief Financial Officer

David Call joined Mimecast in May 2023 as Chief Financial Officer. He is an accomplished finance executive with over 20 years of leadership experience in high tech and enterprise software environments. As CFO, Call helps shape the company’s strategic roadmap and plays a key role in helping Mimecast exceed its growth and financial goals, while fostering a collaborative, values-driven culture. Call most recently served as CFO with defi Solutions. Previously, he spent 7 years at McAfee where he served as business unit CFO for both consumer and enterprise security divisions. Call also spent more than 10 years at Intel in various senior leadership finance roles, including their Software & Services Group and the Intel Platform Security Group, before taking a leadership role at McAfee following Intel’s acquisition.

Call has a BS in Accounting from Brigham Young University and an MBA in Finance from UCLA.

Janet Prosper

Chief Human Resources Officer

Janet Prosper was named Chief Human Resources Officer in November 2023. She joined Mimecast in February 2020 as Senior HR Director and has served as interim CHRO since October 2022, and Vice President, Human Resources, since May 2021. Janet leads Mimecast’s diversity, equity, and inclusion initiatives and partners with the executive team to shape the company’s people and organization’s strategic roadmap, driven by 'The Mimecast Way’ values.

Janet has nearly three decades of experience leading HR teams in large, global organizations. A considerable part spent working in software/technology organizations undergoing transformation. She also held senior leadership roles with global responsibilities at CareerBuilder, Ciena and Equifax.

During her career she has led all aspects of human resources: transformation, organizational design, change management, culture and employee offering, talent management, and leader development.

Janet has a Bachelor of Arts degree in Business Administration and Human Resources from the University of Westminster.

Chris Wey

Chief Transformation Officer

Chris Wey joined Mimecast in 2024 as the Chief Transformation Officer. With over 25 years of broad enterprise software experience, Chris will be taking on cross-functional, transformative projects to position Mimecast for sustainable growth.

Most recently, Chris was President of the Data Modernization business unit at Rocket Software, where he led engineering and product management and drove GTM success. Throughout his career, he has held a variety of roles including Corporate Development, Strategic Partnerships, M&A Integration, Engineering, and Sales Operations at Carbonite, Avaya and IBM. His consistent focus has been on driving growth, organically and inorganically, in rapidly evolving IT markets, and building the robust organizational infrastructure to support that value creation.

Chris holds a Bachelor of Science in Electrical Engineering from Boston University. He was born in Switzerland, and he and his four children take every opportunity to return to Europe for family visits.

Rob Juncker

Chief Product Officer

As Chief Product Officer, Rob leads strategy and drives innovation in product management, development and delivery.

Prior to joining Mimecast, Rob served as the Chief Technology Officer at Code42 until the company was acquired by Mimecast in July 2024. At Code42, Rob led the development teams that created Incydr, taking the company from a backup on-premises product to a cloud-delivered cybersecurity solution. Rob continued as a member of Mimecast senior leadership, driving innovation for the Incydr product and engineering teams until he took on the role of Chief Product Officer in February 2025.

Rob brings more than 25 years of security, cloud, mobile and IT leadership experience to Mimecast. Prior to Code42, Rob worked as Vice President of Research and Development at Ivanti, where he led and shaped the company's evolution from IT management technologies to security-focused solutions, with projects ranging from cloud-delivered analytics to hybrid cloud security. Prior to Ivanti, Rob served as senior director of research and development at VMware, a leader in virtualization and hybrid cloud. Rob has published several papers on information technology, security and mobility. His passion for the Software Industry, and keeping a pulse on its future, has made him a high-demand speaker throughout the international community. Rob graduated from Carleton College where he earned a bachelor’s degree in computer science with a concentration in economics.

In his spare time, Rob enjoys spending time with his family.

Mick Paisley

Chief Security and Resilience Officer

Michael Paisley joined Mimecast in 2020 as Chief Security and Resilience Officer. With nearly 20 years’ experience as a CISO in multi-national, highly targeted and highly regulated organizations, Mick is well-versed in operating at the continually evolving intersection of cyber security, resilience, quantitative risk and advanced data analysis.

During his career, Mick has successfully developed and executed efficient threat- and risk-based cyber resilience strategies that have reduced aggregated cyber loss exposure, while enabling colleague’s productivity for several large and complex organizations. Prior to joining Mimecast, Mick was CISO at Verifone Inc a global payments provider. He was previously CSO for Vocalink, a component of the UKs critical National Infrastructure where he successfully led the first formal CBEST testing of any financial services organization with full transparency of the process to key stakeholders. Before that, Mick was responsible for all aspects of cyber resilience, digital risk, e-fraud, business continuity planning and crisis management for Santander UK.

Mick holds a Bachelor of Laws degree and a Master of Science degree in Security and Organizational Risk Management from the University of Leicester.

David Helfer

Chief Customer and Revenue Officer

David Helfer joined Mimecast in January 2023 as Chief Revenue Officer. He is an accomplished go-to-market executive with extensive global leadership experience in highly complex infrastructure and security organizations. As CRO, David will lead Mimecast’s global sales organization and help drive its short- and long-term revenue goals.

Prior to Mimecast, David served as vice president of enterprise sales, Americas at GitLab, Inc. His successful international background also includes time as a senior vice president at F5, leading worldwide channels and EMEA sales based in London, UK. David also spent 14 years at Juniper Networks where he helped grow revenue streams in various executive roles.

David holds a Bachelor of Arts degree in Political Science from Kalamazoo College.

Chris Dollase

General Counsel

Chris Dollase joined Mimecast in October of 2017 as deputy general counsel, vice president and chief compliance officer. In February 2023, he was promoted to general counsel and senior vice president to lead the legal, compliance and assurance, risk and control teams at Mimecast. Chris and his team work to provide business centric legal advice to all of Mimecast. The team maintains Mimecast’s culture of integrity and compliance while delivering on the company’s growth strategy.

Mimecast’s legal team helps 42,000+ customers secure human risk and be successful in an everchanging threat landscape. Chris is an experienced cybersecurity executive who spent 15 years at RSA, The Security Division of EMC, prior to joining Mimecast. He served as lead counsel for RSA and assistant general counsel for EMC and was a member of RSA’s leadership team.

Chris has helped navigate Mimecast through seven acquisitions during his tenure, and most recently played a vital role in Permira’s acquisition in May 2022. Chris holds a Doctor of Law J.D. degree from the University of Maryland Francis King Carey School of Law and a Bachelor of Arts in History from Middlebury College.