I. Introduction

Arbitral tribunals endeavor to ensure the fair conduct of the proceedings. One issue that they may face in this context is deciding whether to allow parties to amend their claims and/or to submit new claims during the arbitration proceedings. Although they may have legitimate reasons for filing new or amended claims, some parties may attempt to use such instrument to delay arbitration proceedings and/or obtain other undue advantages. The question thus arises as to the requirements under which a party should be allowed to submit new claims or to amend already submitted claims during ongoing proceedings.

The present article discusses said question and suggests some answers. As a first step, this article explores the definition of an “amendment of claims” and of “new claims” and seeks to differentiate these from other concepts. The article then gives an overview of the requirements for the amendment of claims and the submission of new ones from a comparative perspective and under selected leges arbitrae and institutional rules. This analysis reveals that the arbitral tribunal usually has large discretion in making its decision on the admissibility of new or amended claims. In order to bring some structure in this regard, the article proposes a framework of factors which an arbitral tribunal may wish to consider when deciding whether to admit or reject new or amended claims.

II. Definitions and Distinction from Other Concepts

Although some national arbitration laws and institutional rules contain specific provisions regarding the requirements for the amendment of a claim or the submission of a new one, they usually do not define what it means for a claim to be “amended” or when a claim must be considered “new”. As will be seen in the following, it is important to define and distinguish the filing of amended and new claims from other types of actions, such as the submission of new facts, the filing of new evidence or the withdrawal of claims. Given that there is no universally accepted definition of the concepts involved, the comments below reflect the authors' understanding of the matter.

The identity of a dispute may be pinpointed by the combination of the prayers for relief and the underlying cause of action.1 Prayers for relief can be defined as the precise indication of the requests the party intends the judgment to rule upon.2 In contrast, the cause of action is “the claim's factual basis, i. e. the whole complex of facts and circumstances from which the claim emanates”.3 As a result, an amended claim will refer either to a change in a party's prayers for relief or to a change in the underlying cause of action.4

A change in the wording of the prayers for relief without changing their meaning or purpose will not in itself be an amendment of the claim.5 For a claim to be considered amended, the change in the prayers for relief must relate to a quantitative or qualitative increase to the prayers,6 rather than a restriction thereof, which may be considered a withdrawal of the claim. Such withdrawal of claims will usually have res iudicata effects,7 unless the opposing party agrees to a withdrawal without prejudice.8

A change in the cause of action is where the facts of the case have fundamentally changed.9 In such a case, a party may amend its claim by changing the prayers for relief based on new facts that change the underlying cause of action. For example, it may increase its damages claim by submitting new facts that show the loss incurred was even larger than it initially assumed.10 This has to be distinguished from the situation in which a party simply submits new facts or evidence to support its original claims, which does not constitute an amendment of the former claim.11

It must also be noted that, where the principle of iura novit curia applies, a party may be allowed to make new legal arguments in support of its claim or to change the legal qualification of its claim (such as basing the same claim in contractual law instead of tort law) even where it may not submit new claims (such as where the tribunal has set a deadline for new claims to be submitted, and this deadline has already expired).12

In contrast to the above, a claim is “new” where it is independent of the previous claims.13

As will be shown below, some national arbitration laws and many institutional rules provide specific guidelines for submitting new or amended claims or counterclaims. The applicable rules may not differentiate between new or amended claims, and scholars commenting on such rules may have a different understanding of new or amended claims than outlined above.

III. New and Amended Claims under National Arbitration Laws

According to most national arbitration laws, new or amended claims will generally be considered admissible during the proceedings, although the arbitral tribunal is granted considerable discretion in its decision on admissibility.

Many leges arbitrae contain specific rules governing new or amended claims in arbitration. For example, § 1046(2) of the German Civil Procedure Code and Art. 23(2) of the UNCITRAL Model Law provide that either party may amend or supplement its claim or defense during the arbitral proceedings, unless the parties have agreed otherwise, except where the arbitral tribunal finds it inappropriate to allow such amendment having regard to the delay in making it without sufficient justification. This is also understood to encompass making new claims.14

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1. Berger/Kellerhals, International and Domestic Arbitration in Switzerland, 4th ed. 2021, 440, who also name the statement of defense and counterclaim as defining the subject-matter of the dispute.

2. See Perret, Les conclusions et les chefs de la demande dans l'arbitrage international, ASA Bull. 1/1996, 7.

3. Berger/Pfisterer, Article 20, Amendments to the Claim or Defence, in Zuberbühler/Müller/Habegger (eds), Swiss Rules of International Arbitration, Commentary, 2nd ed. 2013, 228.

4. Berger/Kellerhals, International and Domestic Arbitration in Switzerland, 4th ed. 2021, 440.

5. Berger/Pfisterer in Zuberbühler/Müller/Habegger (eds), Swiss Rules of International Arbitration, Commentary, 2nd ed. 2013, 227.

6. For a different opinion in relation to new and amended claims in ICC arbitrations, see Verbist/Schäfer/Imhoos, ICC Arbitration in Practice, 2nd ed. 2016, 133, who consider that “a mere increase in the amount of a claim based on facts that have already been presented in time” do not relate to the “question […] as to whether the parties may add to their claims or bring new claims after the Terms of Reference have been signed”.

7. See Berger/Pfisterer in Zuberbühler/Müller/Habegger (eds), Swiss Rules of International Arbitration, Commentary, 2nd ed. 2013, 227. National arbitration laws and institutional rules may govern the consequences of withdrawal specifically, see for example § 1056(2)(1)(b) German Civil Procedure Code.

8. For a detailed analysis of the topic, see Haller/Keilmann, In Claimant's Hands? Admissibility and Consequences of a Withdrawal of Claim in International Arbitration, J. Int'l Arb. 6/2018, 649 et seqq.

9. Berger/Kellerhals, International and Domestic Arbitration in Switzerland, 4th ed. 2021, 441 et seqq.

10. Berger/Kellerhals, International and Domestic Arbitration in Switzerland, 4th ed. 2021, 442.

11. See Craig et al., Craig, Park and Paulsson on International Chamber of Commerce Arbitration, 4th ed. 2017, 279. See also Perret ASA Bull. 1/1996, 10.

12. See Schneider/Scherer, Art. 182 IPRG, in Grolimund/Loacker/ Schnyder (eds), Basler Kommentar Internationales Privatrecht, 4th ed. 2020, 2057; Schlosser, Das Recht der internationalen privaten Schiedsgerichtsbarkeit, 2nd ed. 1989, 500.

13. Berger/Pfisterer in Zuberbühler/Müller/Habegger (eds), Swiss Rules of International Arbitration, Commentary, 2nd ed. 2013, 228-229.

14. Sachs/Lörcher, Part II: Commentary on the German Arbitration Law (10 Book of the German Code of Civil Procedure), Chapter V: Conduct of the Arbitral Proceeding, § 1046 – Statements of Claim and Defence, in Nacimiento/Kröll/Böckstiegel (eds), Arbitration in Germany: The Model Law in Practice, 2nd ed. 2015, 274 with further indications.

in: SchiedsVZ Zeitschrift für Schiedsverfahren/German Arbitration Journal (German Arb. J) 2/2022, Verlag C.H.BECK und SchiedsVZ - beck-online

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