Marcos Roca

Team Lead - TIWB Secretariat, OECD

2, rue André Pascal
75775 Paris Cedex 16, France
 

Tel: +33 1 45 24 76 22
E-mail: marcos.roca@oecd.org 

Mr. Marcos Roca, assumed the role of Team Leader at the TIWB Secretariat in March 2024, overseeing the coordination, support, and advancement of the TIWB initiative at the OECD in Paris. In this capacity, he collaborates closely with host and partner administrations and with the UNDP to facilitate the implementation of TIWB programmes worldwide. 

Marcos joined the OECD in 2020 as a Tax and Crime Adviser, where he led the work the OECD Task Force on Tax Crimes and Other Crimes and the OECD Academy for Tax and Financial Crime Investigation. Before this, he held prominent positions in the civil service of Argentina, advising senior officials including Cabinet Ministers and lawmakers on matters of public policy and legal reforms. Additionally, he served as an assistant professor and guest lecturer at various universities, publishing extensively in professional publications and media outlets.

An Argentinian and German national, Marcos commenced his career as an investigator in the Public Prosecutions Service. He holds a degree in Law, specialised in tax law, from the Universidad de Buenos Aires, and he earned an MSc. in Criminology and Criminal Justice (with Distinction) from the University of Edinburgh. Besides his native Spanish, he is fluent in English, French, German and Portuguese.

Ahtesham R. Khan

Project Manager - TIWB, UNDP

One United Nations Plaza, DC1-1950
New York, NY, 10017, USA 

Tel: +1 (212) 906-6417
E-mail: ahtesham.khan@undp.org 

Ahtesham R. Khan is Project Manager in the Finance Sector Hub, UNDP, and manages the TIWB initiative for UNDP. He has extensive experience in fiscal policies, tax administration and domestic resource mobilisation. As Officer on Special Duty in the Ministry of Finance, Government of India he worked on BEPS negotiations and tax arbitration cases. Ahtesham was Deputy Director of the Indian Tax Administration whereby he investigated illicit financial flows and cross border tax evasion. As Assistant Commissioner, he conducted tax audits and dealt with complex issues related to tax laws. He has also worked on the Local Currency Bond Markets project of the World Bank and the United Nations Handbook on Taxation of the Extractive Industries published by the Financing for Sustainable Development office, UN-DESA.

Ahtesham has done Electrical Engineering in under-graduation and has dual Masters - Masters in Taxation and Business Laws from NALSAR University, India and Masters in Public Administration with specialization in Advanced Policy and Economic Analysis from SIPA, Columbia University. He is recipient of the prestigious JJ/World Bank Scholarship.

Kalale Mambwe

Project Manager, TIWB Secretariat, OECD

2, rue André Pascal
75775 Paris Cedex 16, France
 

Tel: +33 1 45 24 75 21

E-mail: kalale.mambwe@tiwb.org

Kalale Mambwe, a Zambian-born economist, joined the OECD as the Tax Inspectors Without Borders (TIWB) Project Manager on 1 September 2022.

Kalale has extensive experience in tax audit and policy having worked previously as an auditor on complex transfer pricing cases in various sectors and with a particular focus on addressing some of the most pressing Base Erosion and Profit Shifting (BEPS) challenges facing developing countries. As a manager in the international taxation unit at the Zambia Revenue Authority, Kalale contributed significantly to the introduction of Zambia’s transfer pricing regulations and refinement of its transfer pricing rules.

Kalale also served as a technical committee member of the Future of Resource Taxation, a Project started as an initiative by the Africa Tax Administration Forum (ATAF) and The Intergovernmental Forum on Mining, Minerals, Metals and Sustainable Development (IGF) aimed at taking stock of mining tax systems and consideration of the alternative futures for the extractive industry. Kalale also worked alongside ATAF in providing assistance to other African tax administration’s to help build capacity in transfer pricing.

Kalale has provided training and mentoring to numerous officials of Ministries of Finance, Revenue Authorities and Central Banks of various countries through the Macroeconomic and Financial Management Institute of Eastern and Southern Africa (MEFMI) on international tax and transfer pricing. Before Joining the TIWB, Kalale represented Zambia as a delegate at the OECD Inclusive Framework on Pillar One and Pillar Two.

Kalale has an honours degree in Economics from the University of Namibia and an MBA from the University of Zambia.

Melanie Mathis

Project Co-ordinator, TIWB Secretariat

2, rue André Pascal
75775 Paris Cedex 16, France 

Tel: +33 1 45 24 81 94
E-mail: melanie.mathis@tiwb.org