The Mandaat team

We work as part of a strong team. Our team has people that supplement and enhance each other. A unit of co-operative, driven professionals. People that work hard and play hard, for great results and lots of fun.

Managing Partner

Jan Kalisvaart

Jan Kalisvaart

Managing Partner

After studying business economics in Amsterdam, Jan did develop into an experienced CFO, supplemented with years of experience in the interim market at PWC and later Conquaestor. He left ConQuaestor as a member of the board and responsible for the interim activities. He has also worked as interim professional for many years, in both financial and general management roles at, among others, Unilever Bestfoods and Nevi. In his role as Managing Partner, Jan is ultimately responsible for Mandate and first point of contact for all interim questions in the Netherlands.

M: 31(0)6 11048267
E: jkalisvaart@mandaat.nl

Associate Partners

Diederik van den Biggelaar

Diederik van den Biggelaar

Associate Partner

Diederik began his entrepreneurial career when he was still at University, as one of the founders of renowned student disco Dansen bij Jansen in Amsterdam. Het then moved on to the international world of business, working at Heineken for an extended period of time. He worked in bars & hotels branch as well as international branch. Het left Heineken as the chief export manager for Europe and Japan. After Heineken, Diederik worked at Samas as group executive, GM at de Boer Temporary Structures, owner-manager of Perfecta, founding partner of iKi Beer and as senior partner at Custom Management and thereafter he has been one of the owners of Mandaat for 10 years. After the sale of Mandaat to JBR at the end of 2020, Diederik will remain involved as Associate Partner, with focus on restructuring and doing business in distressed SME environments.
After Heineken, Diederik worked at Samas as group executive, GM at De Boer Temporary Structures, owner-manager of Perfecta, founding partner of iKi Beer, and as senior partner at Custom Management. He has been one of the owners of Mandaat for over 9 years now.

M: +31 (0) 653 948 895
E: dvdbiggelaar@mandaat.nl

Janco Duvekot

Janco Duvekot

Associate Partner

Janco comes from a Sales and Marketing background, with experience at Heineken. He started out there after studying business economics in Rotterdam. At Heineken, he acted as commercial executive at Vrumona, the largest supplier of fizzy drinks in the Netherlands. He subsequently took on various interim management assignments in SME business. Simultaneously he fulfilled several positions in manager/trainers coach roles in field hockey. He joined Mandaat in 2012 and developed the ‘Flexpat’ model, which is all about interim management in locations across the world. With Mandaat joining joining the WIL Group, the London-based Worldwide Interim Leadership Group, Janco has established himself as the lynchpin of Mandaat’s International Desk. After the sale of Mandaat to JBR at the end of 2020, Diederik will remain involved as Associate Partner with focus on the ‘Flexpat’ business among other things.

M: +31 (0) 6 222 01 327
E: jduvekot@mandaat.nl

Officemanager

Tom Linthorst

Tom Linthorst

Officemanager

Tom Linthorst has been the office manager for Mandate for 3.5 years now. He is currently studying Human Resources at the ‘Hogeschool van Amsterdam’.

M: +31 (0)616151698
E: tlinthorst@mandaat.nl