International Arbitration 2025

Seasons Greetings

Mayer Brown's Festive List

Dear Friends and Colleagues As the festive season approaches, we have an early gift for you: our personal pick of the top 10 International Arbitration developments across the globe this year… Mayer Brown’s Festive List returns! The International Arbitration landscape rapidly evolved in 2025 with important legislative reform, insightful challenge decisions, and the integration of AI being a few of the key trends that we report on below. We are proud to work alongside you during these interesting and challenging times. We wish you an enjoyable festive season and look forward to working with you in 2026.

Mayer Brown Victorious in Singapore COURT Jurisdiction Challenge Mayer Brown secured a landmark victory in the Singapore International Commercial Court (SICC) for Frontier Holdings Ltd, overturning an ICC tribunal’s negative jurisdiction ruling against Petroleum Exploration (Pvt) Ltd. The SICC held the parties agreed to international arbitration, not domestic arbitration in Pakistan — the first reported successful challenge of a negative jurisdiction award in Singapore.

From our International Arbitration team

To learn more about our International Arbitration practice, visit mayerbrown.com

"2024 has been a very exciting year with many important International Arbitration developments across the globe. The UK Supreme Court’s decision in UniCredit demonstrates London’s strong commitment to preserving International Arbitration not only in London but across the globe where English law has been applied. This is also supported by the new Arbitration Bill that further improves the legal environment for International Arbitration in London. However, important developments in International Arbitration have also been made across the globe and we capture many of these in our Festive List above, which we hope you enjoy reading." Raid Abu-Manneh Head of International Arbitration (IA), London and Global Leader for IA

3. The Arbitration Act 2025 Comes into Force The Arbitration Act 2025, which came fully into force on 1 August 2025, introduces important amendments to the arbitration regime in England, Wales and Northern Ireland for proceedings commenced from that date. We examine the five most impactful changes for businesses in Part 1 (including a statutory rule for the law governing an arbitration agreement (meaning parties should review their existing arbitration clauses)) and the remaining changes (and their impact) in Part 2. In Part 3, we also summarise what has not changed under the new law.

4. US Supreme Court Rejects "Minimum Contacts" Requirement Under FSIA Overturning a 9th Circuit decision, the U.S. Supreme Court unanimously confirmed that under the Foreign Sovereign Immunities Act (FSIA), parties seeking to enforce arbitral awards against foreign states do not need to show "minimum contacts" to establish personal jurisdiction. This decision clarifies (and streamlines) the process for enforcing arbitral awards against foreign states in US courts, although whether a separate "minimum contacts" analysis is required to satisfy due process obligations remains unresolved.

2. Mayer Brown ACTS IN TWO LANDMARK CASES in the English High Court – K1 et al v B and ADC v Aastar Trading We look at two challenge decisions in the English High Court where our team acted in 2025, and which constituted new points of law under the Arbitration Act 1996. In the first, the High Court held, obiter, that a non-participant may invoke s.72(1) without the 28 day limit in s.70(3), after refusing extensions for time under s.67 and s.68. This case is significant as it considers the application of time limits in the situation of non-parties. In the other, the English High Court dismissed an application to bring a s.68(2)(g) challenge to a London-seated LCIA award, on the basis that s.68(2)(g) is not intended to allow public policy objections which were not raised during the arbitration to be raised under the challenge provisions. However, the court indicated, obiter, that enforcement of domestic awards may be resisted on public policy grounds, despite s.66 not expressly saying so.

5. SAUDI ARABIA’S DRAFT ARBITRATION LAW The Kingdom of Saudi Arabia (KSA) published a draft arbitration law for public consultation (which was open until 24 October 2025), seeking to replace their current arbitration framework and align it closely with international standards. We examine the key proposed changes (which include a default rule on the law governing arbitration agreements and enhanced procedures for challenging jurisdiction) and the potential impacts of the changes (which includes the need to revisit KSA-connected arbitration clauses).

6. Paris Court of Appeal Rules on Pre-Trial Judge’s Jurisdiction Our Paris team have summarised an important Paris Court of Appeal decision of 9 September 2025: Bacilio Amorrortu v Peru, Paris Court of Appeal, Pôle 5, Chambre 16, No RG 24/00774. The Paris Court of Appeal held that (i) in proceedings seeking to set aside an arbitral award, the Court of Appeal itself has jurisdiction to determine whether it may rule on jurisdictional objections not determined by the arbitral tribunal; and (ii) this determination falls exclusively within its remit and cannot be made by the pre-trial judge. Our summary is available on Practical Law.

10. Mexico’s 2025 Judicial Elections and Dispute Resolution In June, Mexico held its first nationwide elections for 2,681 judges, including Supreme Court justices. Marked by low voter turnout and a high rate of invalid ballots, the election raised concerns about transparency, public awareness, and the independence of the judiciary, as most newly elected Supreme Court justices have close ties to the executive branch and the ruling party. We explain considerations for investors, including whether to opt for arbitration instead of Mexican courts and the extent of treaty protection for their existing investments.

8. GERMANY UPHOLDS VALIDITY OF ARBITRATION AGREEMENT WHICH EXCLUDES GERMAN T&C LAW The German Federal Court of Justice confirmed that parties may exclude the application of German law on general terms and conditions (sections 305-310 BGB) in their arbitration agreements without invalidating those agreements (an option unavailable in German litigation as German state courts must apply mandatory T&C law). We take a close look at this pro-arbitration decision and its implications for parties negotiating contracts with a German nexus, including challenge and enforcement implications.

7. Cross-Jurisdictional Clashes Continue In RCA v. Linde Dispute The Ruschemalliance LLC (RCA)–Linde GmbH group dispute, arising from the termination of the parties' EPC contract and complicated by EU sanctions, spilled into complex, multi-jurisdictional litigation. RCA pursued Russian litigation, while Linde and the banks obtained English anti-suit injunctions (ASIs). RCA’s concurrent Kazakh and Dutch actions failed for jurisdictional reasons, and some English ASIs were later lifted due to conflicting Russian court orders and asset restrictions. We examine the dispute which highlights the impact of geopolitics on cross‑border enforcement.

9. AI ARBITRATORS HAVE NOW ARRIVED (IN SOME CASES)! In the first week of November 2025, the AAA-ICDR launched its AI Arbitrator designed to resolve two- party, documents-only construction cases where both parties agree to its use. We discuss the major elements of this AI tool — which has a “human in the loop” — including its limitations and safeguards.

UniCredit v RCA (UK Supreme Court)

To see all the other topics that we wrote about this year, take a glance at our International Arbitration Insights page.

UniCredit v RCA (UK Supreme Court)

"We are grateful to our international arbitration clients around the world for their continued trust and support in Mayer Brown. We wish you a joyful and festive year-end holiday season and look forward to catching up in 2025." Yu-Jin Tay Head of International Arbitration, Asia

"This year we’ve seen a lot of developments potentially impacting foreign investment and the protection of foreign investors’ rights. We have therefore prepared various Legal Insights aimed at foreign investors who may be adversely impacted by significant global events like the ongoing war in Ukraine, Mexico’s controversial judicial reform and Honduras’ decision to denounce the ICSID Convention. We remain at your disposal to assist should your business encounter challenges or simply need a guiding hand. We look forward to continuing to work alongside you in 2025." Dany Khayat Head of International Arbitration & Litigation, Paris

Seasons Greetings

Mayer Brown's Festive List

Dear Friends and Colleagues As the festive season approaches, we have a special gift for you: our personal pick of the top 10 International Arbitration developments across the globe this year……Introducing Mayer Brown’s Festive List! The International Arbitration landscape remains a fast-paced and complex one and we are proud to work alongside you to navigate such interesting and challenging matters. We wish you an enjoyable festive season and look forward to working with you in 2025.

(1) UniCredit v. RCA: UK Supreme Court decision The decision affirms the power of the English courts to protect arbitration agreements (“AA”) governed by English law through the issue of anti-suit injunctions (“ASI”), where parties breach their contractual obligations to arbitrate disputes. We explore the key takeaways from the case - which is the leading authority on ASIs for foreign-seated AAs – focusing on the jurisdictional basis for ASIs, as well as the underlying policy framework. We also explore how the Arbitration Bill will change the position in UniCredit.

From our International Arbitration team

To learn more about our International Arbitration practice, visit mayerbrown.com

(3) The UK Arbitration Bill The UK Arbitration Bill is now being debated in the House of Commons and could be enacted by the end of 2024. We explore the latest amendments to the Bill since it was re-introduced by the Labour government in July 2024. Our Arbitration Act Insights page also went live this year enabling you to follow our detailed commentary on the contents of, and passage of, this bill.

(4) Heirs to the Sultanate of Sulu v Malaysia The Paris Court of Appeal ordered the suspension of set-aside proceedings initiated against the final award rendered in a dispute between the two parties, pending the French Court of Cassation’s decision on a challenge to enforcement of an earlier partial award on jurisdiction in the same arbitration proceedings. This decision highlighted the discretion of the French courts to stay concurrent proceedings, in the interest of procedural economy and good administration of justice, pending the outcome of the first.

(2) Arbitration Amidst Adversity In May 2024, we launched our new interview series, hosted by Volodymyr Yaremko, which delves into the experiences of women in arbitration navigating the challenges (and opportunities) they face while living through the Russian invasion of Ukraine. We captured the personal stories of three remarkable Ukrainian women: Svitlana Romanova (Chief Legal Officer at Metinvest), Olena Perepelynska (Partner and Head of Arbitration at Integrities), and Tatyana Slipachuk (Special Advisor at Sayenko Kharenko).

(5) ArbitrateAD 2024 saw the opening of the new Abu Dhabi International Arbitration Centre (branded "arbitrateAD"), replacing the previous Abu Dhabi Commercial Conciliation and Arbitration Centre ("ADCCAC"). We summarised 12 key features of ArbitrateAD’s new Arbitration Rules, which apply to cases filed with ArbitrateAD on or after 1 February 2024, together with guidance for parties in the region.

(6) Singaporean Conditional Orders In Voltas Ltd v. York International Pte Ltd [2024] SGCA 12, the Singapore Court of Appeal held that (i) an award containing conditional orders could be regarded as a final award that disposed of all remaining claims in the arbitration and (ii) any reservation of jurisdiction in an otherwise final award must be made expressly. This case highlights the importance of tribunals and parties ensuring that an award contains an express reservation of jurisdiction, where it is intended that the tribunal will retain jurisdiction to decide future issues.

(10) HKIAC’s Revised Administered Arbitration Rules HKIAC updated their flagship Administered Arbitration Rules, effective from 1 June 2024. Key changes include: aligning the consequential effect of proper commencement of a single arbitration under multiple contracts with a decision to consolidate two+ arbitrations, powers enabling HKIAC and tribunals to enhance the efficiency of arbitration, making diversity a consideration for appointments, widened scope for electronic communication and new provisions on information security, environmental impact and costs.

(8) New York court upholds lakah award An October 2024 decision by the United States District Court for the Southern District of New York marks the end of the Lakah brothers' challenges to resist being held personally liable under arbitration agreements in Eurobond documents; their unsuccessful appeal highlights that corporate veil piercing remains a powerful tool in New York-seated arbitrations.

(7) Russia: Investment Protection and Arbitration In our newly launched Series, we explore topics focused on the recourse available to international investors who have suffered losses in Russia or Ukraine due to Russia’s invasion of Ukraine. We cover: the US Government's Business Advisory about maintaining Russian operations, the launch of the Register of Damage for Ukraine, the Russian Decree providing for confiscation of US-related assets, the impact of Russian law changes and sanctions on dispute resolution, and navigating arbitrator appointments caught in geopolitical crossfire.

(9) Mexico & Honduras - Developments impacting foreign investors Mexico's controversial judicial reforms, which took effect on 1 October 2024, have injected a considerable level of uncertainty into the Mexican legal landscape. We explore its likely impacts, including: increased risk of investment disputes and trade disputes under the US-Mexico-Canada Agreement plus ramifications for sectors reliant on foreign investment. Separately, following Honduras’ denouncement of the ICSID Convention in February 2024, we recommend that investors with investments in Honduras who have potential claims should quickly analyse their options. We outline potential options for investors.

UniCredit v RCA (UK Supreme Court)

To see all the other topics that we wrote about this year, take a glance at our International Arbitration Insights page.

UniCredit v RCA (UK Supreme Court)

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