The investment treaty network and the tax treaty network comprise more than 3,000 treaties each. The provisions of these treaties generally are highly customized on the basis of the investment flows and economic interests of the contracting States. The number of treaties in force and their customization potentially turn the amendment of these treaty networks in their entirety into a cumbersome and long process. To modify the treaty networks in a swift and coordinated manner, the investment treaty makers and the tax treaty makers almost contemporaneously developed the idea of implementing treaty changes through a single multilateral convention. On 10 December 2014, the United Nations adopted the Convention on Transparency in Treaty-based Investor' State Arbitration, also known as the Mauritius Convention. In addition, on 24 November 2016, the Multilateral Convention to Implement Tax Treaty Related Measures to Prevent Base Erosion and Profit Shifting (BEPS), commonly referred to as the Multilateral Tax Instrument, was concluded under the aegis of the Organisation for Economic Co-operation and Development (OECD). The Mauritius Convention and the Multilateral Tax Instrument share the object and purpose of modifying an extensive number of treaties. However, due to their novelty, little research has been done until now on their common characteristics and differences. The article aims at filling this gap by comparing both multilateral conventions. It also aims at drawing lessons from the analysis of both multilateral conventions that might be of benefit for future modifications of an extensive number of treaties through a single instrument.

Thesis (M.Com. (Taxation))--University of the Witwatersrand, Faculty of Commerce, Law and Management, School of Accountancy, 2014. / With the international platform for cross border investment and economic development growing year on year at a steady pace, it has become apparent that bilateral income tax treaties do not always operate effectively in multilateral tax situations. Global transactions involving more than two states are certainly not uncommon and it could be said that the most fundamental issue in international taxation is double taxation resulting from the taxing rights of different tax jurisdictions that ‘overlap’ with regard to, generally speaking, one taxpayer or one declared income stream. Multilateral tax situations, commonly known as triangular cases, occur where tax incidence on a particular stream of income is triggered in three countries. These situations typically arise where a person who is a tax resident in two respective countries for tax purposes (a dual resident), or a person who is a tax resident in one country and has a permanent establishment in another, is earning revenue of which the source is in a third country. Taxing rights and jurisdictions of the three countries involved could potentially be in conflict with each other and therefore such situations may bring about lawful international triangular taxation or double taxation which will inevitably discourage enterprises from continuing investment and development internationally. Broad multilateral treaties in the income tax arena are not common1, and most treaties are still of a bilateral nature, i.e. generally addressing tax scenarios where only two specific countries are involved. The Organisation for Economic Cooperation and Development’s (’the OECD’)Model Tax Convention states this: There are no reasons to believe that the conclusion of a multilateral tax convention involving all Member countries could now be considered practicable. The Committee therefore considers that bilateral conventions are still a more appropriate way to ensure the elimination of double taxation at the international level.2