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School of Law

Yavuz Selim Sonmez


PhD Student



Thesis title

The Interdependence Between Tax Competition and Tax Avoidance: An Analysis from Practice to Theory


Dr Bernard Schneider and Professor David Southern

Summary of research

There is extensive literature on both tax competition and tax avoidance. However, the existing literature largely regards these two topics as separate, unrelated phenomena. This research argues that this is incorrect and furthermore, that this misperception is driven by the OECD’s emphasis on tax havens. This thesis will argue that this misperception driven by OECD is because the OECD sees itself as the representative of a club of rich-countries. Therefore, it is not willing to deal with tax competition and tax avoidance promotion of the developed countries. Thus, this thesis argues that any serious effort tackling tax avoidance should find an effective way of changing current competition-based structure of international tax law regime.

The OECD has responded to issues since its 1998 Harmful Tax Competition report. The thesis reviews the OECD’s efforts, starting with that report evaluate anti-tax competition measures proposed as part of the ongoing OECD BEPS project. The findings will be examined by putting focus on the possibility of tax cooperation and the effectiveness of the anti-tax avoidance measures in supplementing restrictions on the tax competition. The thesis will argue that, to date, the competitiveness pressure on states created more tax avoidance, not less. It will consider whether the BEPS project is likely to be more effective in dealing with harmful tax competition.  It will then consider what solutions might encourage more effective tax cooperation.


Yavuz is a PhD Candidate at the Centre for Commercial Law Studies, Queen Mary University of London, and a Teaching Assistant in Tax Law Modules at the LLM Programme. He is also the representative of PhD Students at CCLS and organised the Queen Mary Postgraduate Legal Research Conference 2017. While in employment for a law firm in Turkey, Yavuz handled cases related to corporate income tax, VAT and carousel fraud, and worked on the various tax cases. He completed a Master’s degree in Taxation (Queen Mary, University of London), with a dissertation on the topic of Tax Transparency and Country-by-Country Reporting. He also holds a degree in law (Bilkent University). Yavuz holds a scholarship from Ministry of Education of Turkish Republic, and a member of the IFA. He speaks Turkish and English.


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