Third-Party Funding in International Investment Law

Ammar Tanhan

ISBN: 9781041153054

Published: April 2026

Format: Hardcover

Language: English

Publisher: Routledge

Description

Third-party funding (TPF) has grown into a market now estimated at over USD 15 billion, reshaping who can bring — and afford to bring — investment treaty claims. Ammar Tanhan examines how TPF operates inside investor-state dispute settlement (ISDS), where it touches procedural fairness, conflicts of interest, the commodification of justice, and state sovereignty. Set against ongoing reform efforts at UNCITRAL and other institutions, the book combines theory, case law and a comparative survey of current and proposed regulation to offer practical, policy-relevant conclusions on how TPF should be governed.

Key Features

• Traces the financial impact of third-party funding on the volume and value of investment claims
• Analyses conflicts of interest between funders and arbitrators — the regulatory gap most reform efforts have focused on
• Compares current and proposed TPF regulation across jurisdictions and institutions, including UNCITRAL's reform track

Coverage

Seven chapters move from the modern history and mechanics of third-party funding through its financial impact on ISDS, its effect on the quality and quantity of investment claims, the ethical and legal issues it raises, and a proposed framework for balanced regulation.

About the Author

Ammar Tanhan researches and writes on international arbitration and investment law, with a focus on the funding structures reshaping how investment claims are brought and litigated.

Table of Contents

1. Investing in Investment Claims: Third-Party Funding in Context; 2. Understanding Third-Party Funding: Overview of Its Modern History, Legal Framework and Mechanics; 3. The Financial Impact of Third-Party Funding in Investor-State Dispute Settlement; 4. Impact of Third-Party Funding on the Quality and Quantity of Investment Claims; 5. Ethical and Legal Issues Arising from the Use of Third-Party Funding; 6. The Need for a Balanced Approach: Proposed Options for Regulating Third-Party Funding; 7. Conclusions.

Why buy this book?

Third-party funding is one of the most contested — and least systematically analysed — questions in investment arbitration today. This is a timely, comprehensive treatment for any collection serving arbitrators, funders' counsel or investment treaty practitioners tracking the UNCITRAL reform process.

Keywords

third-party funding, TPF, investor-state dispute settlement, ISDS, investment arbitration, UNCITRAL reform, conflicts of interest, investment claims

Target Audience

Investment treaty lawyers, arbitrators, international arbitration practitioners, academics in investment law

Genre

International Investment Law, Arbitration

Q&A

What is third-party funding (TPF) in investment arbitration?
TPF is when an unrelated funder finances a party's investment claim in exchange for a share of any award, a practice now estimated to exceed USD 15 billion in market size.

Does this book cover the UNCITRAL reform process on TPF?
Yes — the book is written against the backdrop of recently completed and ongoing UNCITRAL reform efforts and offers regulatory proposals informed by them.

What conflicts of interest does third-party funding raise in ISDS?
Chapter 5 examines the ethical and legal issues TPF raises, including conflicts between funders and arbitrators, which the book identifies as the area most reform has focused on.

Who is Ammar Tanhan?
Ammar Tanhan is a researcher and practitioner specialising in international arbitration and investment law.

Where can I buy Third-Party Funding in International Investment Law?
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