The Mauritius Convention on Transparency and the Multilateral Tax Instrument: models for the modification of treaties?

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.