EU signs the Mauritius Convention on Transparency in Investor-State Arbitration

The European Union (the EU) signed the United Nations Convention on Transparency in Treaty-based Investor-State Arbitration (the Mauritius Convention or the Convention) on 2 July 2024, after the Council of the EU had approved its signature last month.

The background to the Mauritius Convention is covered in our earlier blog posts here and here. In summary, the Convention seeks to increase the transparency of investor-state arbitrations by promoting public access to documents and hearings. It does so by extending the applicability of the UNCITRAL Rules on Transparency in Treaty-based Investor-State Arbitration (the Rules on Transparency) to investment treaties concluded before 1 April 2014. The Rules on Transparency apply by default to UNCITRAL-governed disputes under investment treaties signed after that date unless the parties to the treaty specify otherwise.

Under the Mauritius Convention, the Rules on Transparency apply to any investor-state arbitration, whether or not subject to the UNCITRAL rules, in the following circumstances:

• The treaty under which the arbitral proceedings are brought was concluded before 1 April 2014;
• The respondent's state and the claimant's state are both parties to the Convention; and
• Neither the respondent's state nor the claimant's state has made reservations under the Convention to disapply the Rules on Transparency. The Rules on Transparency also apply where the respondent has not made a reservation under the Convention and the claimant has agreed to the application of the Rules on Transparency.

The Rules on Transparency impose relatively wide-ranging obligations on parties to investor-state disputes. Among other features, the Rules provide that:

• The disputing parties must publish certain information, including the names of the parties to the dispute, the economic sector involved and the treaty under which the claim is being made (Article 2). Publication is to be made by providing documents to the Secretary-General of the UN, or an institution named by UNCITRAL;
• The disputing parties must make certain documents available to the public, including in particular the parties’ written submissions and any awards handed down by the tribunal, along with expert reports and witness statements filed in the proceedings upon request to the tribunal (Article 3);
• The arbitral tribunal, after consultation with the parties in dispute, may permit a third party (who is not a disputing party or a non-disputing Party to the treaty), to file a written submission regarding a matter within the scope of the dispute (Article 4);
• The arbitral tribunal must allow (subject to a safeguard on disruption of the proceedings), or, after consultation with the disputing parties, may invite, submissions on issues of treaty interpretation from a non-disputing Party to the treaty (Article 5);
• Hearings for the presentation of evidence or for oral argument should be held in public. (Article 6); and
• Such provisions are subject to exceptions in respect of certain types of confidential information or where dissemination of information would jeopardise the integrity of the arbitral process (Article 7).

The Mauritius Convention came into force on 18 October 2017. Both states and regional economic integration organisations can become party to this treaty and, to date, it has been signed by 23 states and ratified by nine states.

Approximately 1,200 agreements involving EU Member States fall under the scope of the Mauritius Convention. As a next step, the Mauritius Convention will be ratified by the EU after approval of the European Parliament. The EU Member States will subsequently have the option to ratify, accede to or approve the Mauritius Convention. Such ratification will bring any arbitral proceedings under pre-1 April 2014 treaties between (i) the ratifying EU Member State or its nationals and (ii) another Convention state or its nationals within the scope of the Rules on Transparency. This is a significant development, not least since the integration of the EU as a delegation during the relevant UNCITRAL Working Group sessions was not uncontroversial at the time the Convention was being negotiated.

The authors would like to thank Annabelle Proepstl for her assistance in preparing this blog post.