Ekibimiz

Hendrik-Jan van Duijn

Education

In 1998, Hendrik-Jan was awarded a fully-certified Bachelor’s Degree in Accounting Administration Consultancy. He subsequently studied Tax Law in Leiden. Since 2002, Hendrik-Jan has been a member of the Nederlandse Orde van Belastingsadviseurs.

Career

Hendrik-Jan specializes in Partnership and Dividend Taxation, particularly in cross-border investments, mergers and take-overs, partnerships and industrial restructurings. In 2002, he began working with BDO. 4 years later, in 2006, he moved to PwC. In 2008, he moved to New York to work as a tax consultant. While there, he gave advice to US and Canadian businesses wishing to expand or streamline investments, either in or via the Netherlands, as well as to Dutch companies investing in the US and Canada.

Experience

With more than 15 years’ experience in the area of Dutch Corporate and Dividend Taxation, Hendrik-Jan has built up an impressive record of service. In 2011, he set up Duijn’s Tax Solutions and has seen it grow into a successful taxation consultancy. Hendrik-Jan is also behind the creation of many networks. He is, among other things, co-founder of Doing Business in, a network of specialists in the Netherlands and abroad, and of Pro-tp, through which he, along with his partners, offers international transfer-pricing advice. As a specialist in international Tax Law, he also writes for the IBFD.

Joost de Leeuw

Education

In 2007, Joost began studying Law at the University of Amsterdam, having previously studied for his Bachelor’s Degree in Russian Language and Culture. Due to his wide variety of interests, Joost has successfully completed Master’s Degrees in both Criminal and Tax Law. In 2015, he completed his studies with a thesis on participation exemption. Joost is an aspiring member of the Nederlandse Orde van Belastingsadviseurs, which means that he closely follows the latest developments in (international) tax law. He also participates in seminars organized by various bodies, such as the Ministry for Finance, the Chamber of Commerce and the University of Lausanne.

Career

After a short period as a journalist and translator, Joost has found his calling in the legal world. With business in his blood, he has always been attracted to entrepreneurship. During his studies, he was struck by the enormous inequality between the tax possibilities for multinationals and those for SMEs. He feels that this is too disruptive to the markets. Therefore, it is Joost’s ambition to make tax benefits accessible to all entrepreneurs. In this area, he is committed at both a policy and client level. After three years with DTS, Joost is currently working as tax manager and is, among other things, responsible for the Asia Desk.

Experience

“I find the best thing about my job being that moment when a client realizes just how valuable good tax advice can be. The difference between what a company pays in taxation before and after our advice is often much greater than the profit made through a reorganization or an advertising campaign. Thus, tax advice has also added value in a commercial sense and is indispensable in every business plan.”
As a tax consultant, Joost is never doing the same thing every day, because no client is the same. He advises companies and investors in diverse sectors and countries. Applying the innovation box prior to a tech start-up, for example, is completely different to giving transfer-pricing advice to a food importer, but both are nevertheless in the area of partnership taxation.

Kim Sinnige

Education

In 2001, Kim completed her Fiscal Economics training at the Hogeschool voor Economische Studies (HES) in Amsterdam. She subsequently studied Fiscal Law in Leiden. Upon completion of her studies, she specialized further through the Nederlandse Orde van Belastingsadviseurs (NOB or Dutch Association of Tax Consultants).

Career

Before completing her studies in Amsterdam, Kim began her career as a VAT consultant with Deloitte. 9 years later, Kim became a partner at A. Sinnige Administratiekantoor. At the same time, she set up her own consultancy firm, Sinnige Btw-Advies. Since then, Kim has seen her business develop into a successful consultancy firm. Along with this, she writes advice for Indicator BV and Kluwer Avanzer. Since 2014, Kim has been working with DTS.

Experience

Kim is an experienced all-round VAT advisor. She specializes in, among other things, VAT advice in the areas of international trade and financial services, real estate, education, healthcare, and sports. On top of this, she deals with national and international VAT registrations and VAT returns, and writes for diverse trade magazines.

Wefa Ismail

Education

In 2015, Wefa started her studies in Law at Radboud University in Nijmegen and subsequently pursued a Master’s degree in Tax Law. She also delved into Transfer Pricing and completed various courses in this field.

Career

In 2020, Wefa began her career as an intern at DTS Duijn’s Tax Solutions. After her internship, she joined the company as a paralegal and was later promoted to Junior Tax Advisor. During this period, she also assisted with several incorporations at our partner company, Company NL.

Experience

Currently, Wefa is an invaluable asset to our DTS team in Amsterdam – specializing in Transfer Pricing and focusing her work on the tax implications of protective levies and 30% scheme procedures. She thrives on tackling complex issues, always up for a challenge, and never backing down from testing her skills. Wefa has become an integral part of the team – contributing her expertise to ensure successful outcomes. She finds great satisfaction in her work and the results it yields.

Joe Franssen

Education

Joe started his academic journey by enrolling in the MBO-Legal Administrative Assistant program in 2017. Building on this foundation, he pursued a degree in HBO-Finance, Tax, and Advice at the Hogeschool van Arnhem, commencing in 2019. In 2022, Joe completed the minor “Fiscal advisor of the future in combination with applied Business Analytics & Innovation” adding a cutting-edge dimension to his expertise. The finalization of his academic journey occurred in 2023, with the completion of his Bachelor’s degree in HBO-Finance, Tax, and Advice.

Career

In January 2022, Joe initiated his professional career, aligning his passion for taxation with practical experience. Currently, Joe holds the position of Head of Personal Income Tax at DTS. He collaborates closely with senior professionals on Corporate Income Tax matters. Joe is committed to providing professional services, ensuring a comprehensive approach to their fiscal needs.

Experience

With a tenure of two years at DTS, Joe has actively contributed to the dynamic landscape of tax compliance. His responsibilities extend to providing invaluable support to seniors, demonstrating versatility in handling a spectrum of fiscal matters. His dedication to making tax compliance accessible and comprehensible underscores his commitment to the success of both DTS and its clients.

Jiri de Groot

Education

Jiri began studying Law at the University of Amsterdam (AUAS) in 2019. He minored in “Legal Problems In A Digital Society” in 2021. He graduated with a Bachelor’s degree in 2023.

Career

In February 2022, Jiri came in at DTS as an intern and his interest in the fiscal world has since been sparked. During his time at DTS, he is constantly broadening his understanding of tax law, so he can provide clear advice to the clients of DTS and efficient assistance to our seniors.

Experience

Jiri has been building his resume at DTS for over a year now and is committed to making tax compliance as understandable and accessible as possible. Jiri’s work is causally related to the diverse work of the seniors of DTS due to him providing assistance to them. This means that Jiri’s work varies from day to day and that he can assist our clients with matters across the entire fiscal spectrum.

Serkan Yilmaz

Education

Serkan completed the European Law School bachelor’s program and subsequently the Master’s in Tax Law at Radboud University in Nijmegen. During his studies, he developed a particular interest in tax law, with a growing focus on VAT.

Career

During his master’s program, he completed an internship at an internationally operating company, where he gained exposure to various tax disciplines. It was during this time that Serkan discovered his specific interest in VAT. After this internship, he joined DTS Duijn’s Tax Solutions as a VAT intern, where he was immediately involved in the VAT practice. Over time, Serkan progressed from intern to his current role as a fully qualified VAT advisor.

Experience

The diverse client base Serkan works with has allowed him to gain valuable experience across a wide range of industries, from international trade in goods to electronic services. This has enabled him to approach complex VAT matters from different angles and to provide clients with proactive, tailored advice on both domestic and cross-border transactions.

Annerie van den Heever

Education

Annerie obtained her Financial Accountant diploma in 2019 from the Institute for Certified Bookkeepers. Since then, she has continued to expand her knowledge in financial administration and accountancy.

Career

In June 2025, Annerie joined DTS Duijn’s Tax Solutions as a Financial Specialist. With her solid financial background and precise working style, she supports both internal processes and clients in the areas of administration and financial reporting.

Experience

Before joining DTS, Annerie gained valuable experience in the financial services field, further developing her analytical skills and attention to detail. Her passion for structure, numbers, and client-focused service is clearly reflected in her work. She embraced her new role with confidence and now plays an important part in supporting both the team and its clients.

Hugo-Joost van Duijn

Education

Hugo-Joost completed his education at the LTS, specialising in carpentry and furniture making, and completed a course in CNC technology. He is currently taking various financial courses to further develop his accountancy skills.

Career

After years working in the construction and interior design industry, he decided to join DTS Duijn’s Tax Solutions as a bookkeeper in 2024.

Experience

After retraining as an accountant, this field proved to be an excellent fit for him. He is now fully committed to further expanding his financial knowledge.

Monica Tanase

Education

Monica began her educational journey with a degree in marketing and sales, which fueled her enthusiasm for business growth and development. She is currently pursuing an MBA programme, where she is dedicated to deepening her knowledge of global business strategies and leadership. This journey underlines her commitment to lifelong learning and her pursuit of excellence in her professional life.

Career

Monica has accumulated experience in developing strategic partnerships and expanding market reach across the globe. She currently serves as a Business Developer at DTS Duijn’s Tax Solutions, where she builds on her experience by facilitating growth and success for both local and international businesses.

Experience

At DTS, Monica has made connections with experts both within the Netherlands and internationally. Her work focuses on connecting/networking with experts to provide the most informed and effective service for the customers.

Krithika Sivakumar

Education

Krithika completed her Bachelor’s degree in Commerce and Accounting in India, specializing in International Economics. Her academic background included a strong focus on international business, corporate accounting, cost accounting, and fiscal economics. This combination of economics and accounting has provided her with a solid analytical foundation—one that has made her particularly well-suited for the field of Transfer Pricing, where financial, economic, and business principles intersect.

Career

Krithika began her career at Ernst & Young GDS, working in U.S. corporate income tax compliance. During this period, she supported multinational clients across a wide range of industries, including retail, real estate, pharmaceuticals, and medical equipment. She developed strong expertise in tax accounting and managing compliance processes for Forms 1120 and 1065, covering U.S. corporate and partnership taxation, and also gained experience with U.S. trust fund reporting. She then joined Ford Motor Company, where she worked on in-house U.S. tax compliance with a focus on GILTI and BEAT.

In 2019, she moved to the Netherlands and transitioned into international tax practice, joining a boutique advisory firm in Amsterdam as a Transfer Pricing advisor. Since then, she has gained over five years of experience in transfer pricing and tax technology, working with organizations undergoing digital transformation and tax process automation. Her career combines both in-house and consulting experience, with a strong emphasis on innovation, technology, and cross-border advisory work.

In November 2025, Krithika joined DTS Duijn’s Tax Solutions as a Transfer Pricing Specialist.

Experience

Across her ten-year career, Krithika has worked in multiple areas of taxation, but she has consistently found transfer pricing and tax technology to be the most dynamic and intellectually rewarding. Her exposure to multinational teams and clients across the United States, India, and Europe has strengthened her ability to collaborate in diverse cultural environments and handle complex international engagements. This global perspective, combined with her economic and accounting background, has enabled her to navigate the multifaceted nature of transfer pricing and deliver practical, tailored solutions in an international setting.

Süheyl Karakaya

Education

Süheyl studied law at Istanbul University and later completed two master’s degrees in tax law, including an LL.M. in International Business Taxation at Tilburg University, supported by an EU Excellence Scholarship.

Career

Before joining DTS in mid-2025, he worked for two years at a top-10 accounting firm in the Netherlands as a transfer pricing specialist. He was also responsible for the Turkey desk.

Experience

He has experience advising mid-sized and multinational companies on transfer pricing matters, including policy design, supply chain alignment, and business and legal structure optimisation. Süheyl is also enrolled with the Istanbul Bar Association and speaks Turkish, English, Dutch, and German.

Rob Zoontjens

Education

In 2006 Rob completed his studies at Tilburg University. With a background in Fiscal Economics and Controlling, he started a specialization program that resulted in his accreditation by the NOB and extensive international training in the field of transfer pricing.

Career

After studying Fiscal Economics and Controlling, Rob discovered the perfect overlap of both disciplines within PwC’s transfer pricing department. For more than ten years, he refined his expertise as a transfer pricing consultant. Rob then moved to an internal position as Transfer Pricing Director at the world’s largest producer of generic medicines. In this capacity, he oversaw numerous transfer pricing aspects for numerous entities in no less than 37 countries. In 2018, Rob founded his own consulting firm, with a focus on advising medium-sized and large multinational companies. He has been with DTS since the beginning of 2023.

Experience

After many years of experience as a transfer pricing planning consultant and in-house expert, Rob has in-depth knowledge of value chain transformations, supply chain planning, transfer pricing optimization, legal disputes, and compliance projects.
With his technical knowledge and practical experience, he excels in developing robust strategies and work plans for global enterprises. For example, he skillfully navigates the complexities of multinational compliance projects, ensuring that the complexities of the different countries involved are expertly managed throughout the process.