After training as a business economist in Amsterdam, Jan developed into a very experienced CFO, supplemented with more than 10 years of experience in the interim market at PWC and later Conquaestor. In recent years, Jan was a member of the management of Conquaestor and responsible for the interim activities. He has also worked for many years as an interim manager in both financial and general management roles, including at Unilever Bestfoods and Nevi. In his role as Managing Partner, Jan is ultimately responsible for Mandaat and the first point of contact for all interim questions in the Netherlands.


Established in 2000, Mandaat has become a leading Interim Management provider both nationally and internationally. The company aims to be practical and personal, focused on solutions and results. Mandaat joined WIL Group in 2016, to strengthen and grow its international footprint. Its objective is to provide managerial support so that clients are able to drive successful business implementations.

Underpinning that objective, Mandaat supports its clients by providing highly experienced management professionals, as well as coaching and advice for organizations in challenging times. It also provides Flexpats – where experienced Dutch Interim Managers are expatriated to overseas subsidiaries of Netherlands-owned companies.

Via its strong Dutch network, Mandaat selects high performing professionals with specific functional and industry related background. Mandaat’s executive partner Jan Kalisvaart and the associates Diederik van den Biggelaar and Janco Duvekot are experienced Interim Managers themselves.

This has created Mandaat’s unique personal approach, where the company seeks to establish what type of specialist the client needs.  Its expertise has led Mandaat to become the recommended firm among banks in Holland to assist with the recovery and restructuring of companies in distress.

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Contact Details


Het Rond 6a,
3701 HS Zeist,
The Netherlands

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+31 (0)88 626 3228


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