Supervisory Board

Mazars in the Netherlands’ Supervisory Board (SB) is responsible for guaranteeing the public interest and aims to improve the quality and independence of our services. The Supervisory Board supervises the Mazars Executive Board and the entire organisation. Among others, the Supervisory Board is responsible for the policy regarding future board nominations and the remuneration and quality policy.

Pieter Jongstra (Chairman)

In June 2018, Pieter Jongstra (1956) concluded his role as chairman of the board of the Royal Netherlands Institute of Chartered Accountants. In addition, he has been a member to APG’s Supervisory Board from 2015 – 2023, the last three years as chairman. Pieter is also chairman to the Supervisory Board at CZ. Jongstra has been working for EY for 32 years. He joined EY in 1982 and left the EY partnership on 30 June 2014. At EY, he held (inter)national management positions for more than 15 years, of which the last 4.5 years as chairman to the Board of Directors in the Netherlands. At EY Pieter has always conducted an accountancy practice of mainly internationally operating listed and family-owned businesses. Since 2015 he has had several supervisory board memberships, regularly in the role as chairman. In his roles, he is especially motivated when he can improve an organisation through change. Diversity and sustainability are common threads running within his managerial career.



Mariëtte Turkenburg

After studying Fiscal Economics (Tax) at Tilburg University, Mariëtte Turkenburg (1960) joined Loyens & Loeff, where she worked mainly in the international tax practice. Within Loyens & Loeff, she also held many management positions, for instance in HR. For many years she was the partner in charge of managing the Compliance practice and thus responsible for the professional management of staff in the tax practice. Mariëtte has extensive experience in supervisory and managerial positions. She chairs the board of Tilburg University Fund and until recently she was the chair of ‘Stichting Talent naar de Top’. 




Erna Versteegden

Erna Versteegden (1967), organisation advisor and lecturer, built an international career after her studies. In the early 90s, Erna was asked by EY to shape marketing, communications and sales. She continued her career at EY as Company Secretary and Director of Operations for the EMEIA Audit Board. With a background in Marketing and Communications, Leadership Behaviour (Harvard Business School) and Neuroscience (Columbia University), Erna was also educated as a team and executive coach at Phoenix education. After a period abroad she currently works as a consultant for diversity / inclusion and change processes and operations at various organisations. She is also active in various supervisory positions and holds a number of governance roles.



Remco Vlemmix

Remco Vlemmix joined Procter & Gamble after studying Technical Business Administration at Eindhoven University of Technology. He continued his career at McKinsey & Company where he advised a large number of companies in various sectors, including Banking. His expertise is in performance management, process optimisation and digital transformation. From 2019 - 2022, he served as Chief Operating Officer at Fourthline, a tech scale-up focused on KYC (Know Your Customer). Currently, Remco is Chief Operating Officer for tech scale-up staffyou and provides individual coaching for managers and consultants.