Anqi Wang, Ph.D. (2021), University of Bern, is a research fellow at the World Trade Institute. Her research focuses on the reform of international investment regime and dispute settlement. She has published articles on international investment arbitration and investment policy.

• AcknowledgementsAbbreviationsIntroduction1 History of the mfn Clause in International Law1 The Evolution of the mfn Clause in International Trade Law1.1 The Genesis of the mfn Clause in the Middle Ages: From the 11th to the 16th Century1.2 The Appearance of Conditional and Unconditional mfn Clauses: The 18th and 19th Centuries1.3 The Status of the mfn Clause during an Unstable Period for World Trade: The 20th Century Onward2 Incorporation and Development of the mfn Clause in International Investment Law2.1 The mfn Clause in the Colonial Era2.2 The mfn Clause in the Post-colonial Era2.3 The mfn Clause in the Global Era2.4 The mfn Clause in the Rebalancing Era3 Codification Efforts by the International Law Commission4 Conclusion2 Interpretation of the mfn Clause1 Customary International Law1.1 The Expressio Unius est Exclusio Alterius Principle1.2 The Ejusdem Generis Principle1.3 The Contemporaneity Principle2 Articles 31 and 32 of the vclt2.1 Article 31 of the vclt as Containing the Core Principles of Treaty Interpretation2.1.1 Should Interpreters Follow the Textual or Teleological Approach to Treaty Interpretation?2.1.2 Subsequent Agreements and Practices2.1.2.1  Subsequent Agreements2.1.2.1.1 Joint Interpretation Authorized by Treaty Texts as Subsequent Agreements2.1.2.1.2 Other Forms of Joint Interpretation2.1.2.1.3 Non-disputing Party Submissions2.1.2.2 Subsequent Practices2.1.3 Good Faith Principle2.2 Article 32 of the vclt as Containing Supplementary Methods of Treaty Interpretation3 The Role of Arbitral Precedents4 Conclusion3 Applying the mfn Clause for Higher Substantive Treatment1 The Scope of Treatment Covered by mfn Clauses in iia s1.1 The Beneficiary of mfn Treatment (Ratione Personae)1.2 The Temporal Dimension of mfn Treatment (Ratione Temporis)1.2.1 The Temporal Scope of the mfn Clause1.2.1.1  Prospective Formulation of mfn Clauses1.2.1.2 Pre/Post-establishment Approaches to mfn Clauses1.2.2 The Temporal Scope of Treaties1.2.2.1  Ratione Temporis and the Basic Treaty1.2.2.2 Ratione Temporis and the Third-Party Treaty1.3 The Subject Matter of mfn Treatment (Ratione Materiae)1.4 Exceptions to mfn Clauses2 mfn Clauses and Substantive Treatment2.1 De Facto Breaches of mfn Clauses2.1.1 “In Like Circumstances”2.1.2 “Less Favorable Treatment”2.1.3 Burden of Proof2.1.4 Discriminatory Intent2.2 Invoking an mfn Clause in Pursuit of Obtaining a Higher Standard of Protection2.2.1 The Incorporation of Fair and Equitable Treatment (fet) Clauses2.2.2 The Incorporation of Full Protection and Security Clauses2.2.3 The Incorporation of Expropriation Clauses2.2.4 The Incorporation of Umbrella Clauses2.2.5 The Incorporation of Other Substantive Treatment3 Concluding Remarks4 Applying the mfn Clause to Avoid Procedural Preconditons1 The Discussion Started by the Maffezini Case2 Exhaustion of Local Remedies and Dispute Settlement Provisions2.1 Exhaustion of Local Remedies?2.2 Jurisdiction or Admissibility?2.2.1 Requiring Remedies to Be Pursued in Local Courts as an Issue of Admissibility2.2.1.1 The Failure by Tribunals to Properly Apply the Ejusdem Generis Principle2.2.1.2 Public Policy Considerations2.2.1.3 Neglect to Consider the Precise Formulation of Dispute Settlement Clauses2.2.2 Requiring Remedies to Be Pursued in Local Courts as an Issue of Jurisdiction3 What Constitutes “More Favorable” Treatment?3.1 The Approach Considering Domestic Court as Less Favorable3.2 “Fork-in-the-Road” Requirements3.3 The Risk of Treaty-shopping: The Siemens Approach4 Conclusion5 Applying the mfn Clause to Avoid Jurisdictional Obstacles1 State Consent in Investment Arbitration2 Cases Where Tribunals Refused to Establish Jurisdiction via the Application of an mfn Clause2.1 Application of mfn Clause to Establish Jurisdiction Ratione Personae2.1.1 Broadening the Definition of “Investment”2.1.2 Avoiding Legality Requirements2.2 Bypassing Limitations Contained in Dispute Settlement Provisions2.3 Replacing Dispute Settlement Provisions in a Basic Treaty2.4 Applying the Basic Treaty Retroactively3 Cases Where Tribunals Established Jurisdiction via the Application of an mfn Clause3.1 Bypassing Limitations Contained in Arbitration Provisions3.2 Replacing the Chosen Forum for Dispute Settlement3.3 Manufacturing Jurisdiction through an Application of an mfn Clause4 Can Jurisdiction Be Founded on the Basis of an mfn Clause?4.1 Limitation of the Traditional Interpretive Methods4.2 The Incorrect Application of the Ejusdem Generis Principle4.3 Are the ilc Guiding Principles a Way Out?5 Concluding Remarks6 Conclusion1 Current Drafting Trends in Relation to mfn Clauses1.1 Marginalization of the mfn Clause1.1.1 Soft Commitments1.1.2 The Total Absence of an mfn Clause1.2 Refinement of the mfn Clause1.2.1 Retraining mfn Clause From Substantive Obligations1.2.2 Clarifying “in Like Circumstances”1.2.3 Excluding Investor-State Dispute Mechanism From mfn Treatment2 A More Balanced Approach to mfn InterpretationBibliographyTable of MaterialsIndex