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Interpretation of IIAs: What States Can Do ?

Report by UNCTAD, 2011

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This note is divided into three parts. Part one describes the shared authority of States and tribunals in the interpretive process, and sketches some of the current deficiencies in investment arbitration. It advocates a greater involvement of States in the interpretive process, but also considers limitations to a more proactive role of the contracting parties. Part two presents international law principles of interpretation and explains how they can guide States in their actions towards fostering a “better” (i.e. more rigorous, consistent and coherent) interpretation of IIAs. Finally, part three sets out different tools States may employ to guide arbitral tribunals in the interpretation of IIAs.


I. Introduction
Recent years have seen growing
concerns with investor-State dispute
settlement (ISDS). As investors
continue using ISDS to challenge host
countries, their claims increasingly also
touch upon regulations in the public
interest, such as policies to promote
labour or human rights, protect public
health or preserve the environment.
Recent challenges against tobacco
marketing and packaging restrictions
in Uruguay and Australia, adopted, in
part, to implement the World Health
Organization Framework Convention on
Tobacco Control (FCTC) are worrisome
examples. Confidence in the ISDS
process is further compromised by
concerns related to the quality and
predictability of the awards issued
by tribunals: some arbitral decisions
have resulted in inconsistent findings
or have lacked sound reasoning,
sometimes as a result of poor treaty
interpretation. Taken together, these
developments risk undermining
the legal security, coherence and
predictability of the IIA regime (see
infra section II.2).

• International investment agreements (IIAs) are

concluded by States. Where IIAs refer to investor-State
dispute settlement (ISDS), arbitral tribunals interpret IIA
provisions in the context of an ISDS case.

• Some of these interpretations have raised concerns,
because of a perceived lack of consistency, predictability
and quality.

• As masters of their IIAs, States can be more proactive
in asserting their interpretive authority to guide tribunals
towards a proper and predictable reading of IIA

• States have various tools at their disposal (e.g. unilateral,
bilateral and multilateral ones).

• Interpretive considerations may come into play at all the
stages in the lifetime of an IIA, including the drafting,
conclusion, application, dispute settlement and post-
dispute stage.

• These interpretive tools constitute a complementary
means for States – alongside treaty re-negotiations and
amendments – for addressing some of the challenges
the IIA regime faces today.


Note: This report may be freely cited provided appropriate acknowledgement is given to UNCTAD
and UNCTAD’s website is mentioned (www.unctad.org/diae).

1 This Note is based on background research UNCTAD commissioned to Andrea Saldarriaga to analyse the interpretation of treaties
in the context of ISDS. The results of her extensive research on the issue will be published shortly as an independent article in an
international law journal. The drafting of this IIA Issues Note was undertaken by Wolfgang Alschner, with guidance and inputs by Anna
Joubin-Bret, Sergey Ripinsky and Elisabeth Tuerk and support from Peter Sauer. This Note also benefited from comments by Facundo
Perez Aznar, Barry Appleton, Nathalie Bernasconi, Robert Howse, Katja Gehne, Christina Knahr, Markus Krajewski, Ursula Kriebaum,
Andrew Mitchell, Joost Pauwelyn, Anthea Roberts, Andrea Saldarriaga, and Tania Voon.

No. 3
December 2011





In the recent past, States have started reacting to the challenges emerging from the
current ISDS system. Some countries have terminated their investment treaties and
withdrawn from ISDS, or certain aspects of it – an option that raises a number of
complex and novel legal questions.2 Others have worked to improve the treaty language
that is at the origin of controversial claims3 or challenged ISDS awards once they have
been issued.4

As a further alternative, States can take a more proactive attitude when it comes to the
interpretation of IIA obligations. In particular, they can foster a more predictable and
coherent reading of treaty terms. This IIA Issues Note aims to highlight the potential
role of interpretive approaches to address some of the challenges today’s ISDS system
poses for investment stakeholders around the globe. The Note makes a number of
innovative suggestions, some of which remain untested in their practical application. It
does not, however, suggest that interpretation would be a tool for amending or changing
the content of a treaty, nor does it aim at criticizing the legal reasoning developed
by ISDS tribunals or seek to make direct suggestions to arbitrators. Moreover, it
should be noted that no single solution will prove sufficient to remedy all the system's
inadequacies. Nor will each option suit every stakeholder. Nevertheless, the note aims
to provide “value added” by shedding some light on the relatively unexplored topic of
interpretation that is highly relevant for addressing current challenges facing the IIA
regime, with a view to fostering debate and informed decision-making by investment
policy makers and affected stakeholders.

This note is divided into three parts. Part one describes the shared authority of
States and tribunals in the interpretive process, and sketches some of the current
deficiencies in investment arbitration. It advocates a greater involvement of States in
the interpretive process, but also considers limitations to a more proactive role of the
contracting parties. Part two presents international law principles of interpretation and
explains how they can guide States in their actions towards fostering a “better” (i.e.
more rigorous, consistent and coherent) interpretation of IIAs. Finally, part three sets
out different tools States may employ to guide arbitral tribunals in the interpretation of

II. Interpreting IIAs: Actors, Challenges
and Limitations

The legal conclusion reached when applying the abstract rules of an IIA to the facts of a
particular case often hinges on the critical intermediate step of interpreting the terms of
the IIA. Interpretation delineates the scope of rights and obligations in IIAs and thereby
helps distinguish between those acts that constitute an interference with investors’
rights as set out in an IIA and those that fall within a State’s legitimate right to regulate
as recognized in international law. Carefully delineating this borderline is particularly
important in investment law, where disputes proliferate in sensitive public policy areas
and where broad and often vague protective treaty standards are common.

IIAs are inter-State treaties governed by public international law. Hence, investor-State
dispute settlement proceedings, in contrast to commercial arbitrations, take place
against a public international law background. It follows that unless an IIA specifies
otherwise, arbitral tribunals have an obligation to interpret IIAs – like any other
international treaty – following the general international law rules of treaty interpretation.
These rules are primarily embodied in the Vienna Convention on the Law of Treaties
(VCLT).5 A rigorous application of interpretation rules by tribunals contributes to legal

2 UNCTAD IIA Issues Note, Denunciation of the ICSID Convention and BITs, December 2010, http://www.unctad.org/en/

3 UNCTAD Series on Issues in International Investment Agreements (A Sequel) on Most-Favoured Nations Treatment (Fair
and Equitable Treatment and Expropriation forthcoming) available at http://www.unctad.org/iia.

4 UNCTAD IIA Issues Note, Latest Developments in Investor-State Dispute Settlement, March 2011, http://www.unctad.
org/en/docs//webdiaeia20113_en.pdf. It has to be noted that judicial review of arbitral awards by annulment committees
(under the ICSID Convention) or national courts (outside the ICSID system) is primarily intended to safeguard the procedural
rights of the disputing parties and not to review the substantive outcome of the award.

5 Gardiner, Richard K.,Treaty Interpretation (New York: Oxford University Press), 2008, pp. 20ff.


predictability and protects the expectations of States on how treaty standards will be

1) Shared interpretive authority between
States and tribunals

In the interpretation of IIAs, both arbitral tribunals and contracting States have a role to
play. By introducing an ISDS mechanism into a treaty, States delegate the task of resolving
investor-State disputes to international tribunals. This delegation confers arbitrators with
a certain discretion to give meaning to treaty standards. The interpretive authority of
arbitral tribunals, however, is not absolute. First, it is conditioned by principles of treaty
interpretation. Second, it is shared with that of State parties to the treaty.

In international law States are the drafters and masters of their treaties. Even though
States have delegated the task of ruling on investor claims to arbitral tribunals,
they retain a certain degree of interpretive authority over their treaties: by virtue of
general public international law, they can clarify their authentic intentions and issue
authoritative statements on the proper reading of their treaties. As the Permanent Court
of International Justice (PCIJ) noted “the right of giving an authoritative interpretation
of a legal rule belongs solely to the person or body who has power to modify or
suppress it.”7 This was later reaffirmed by the International Law Commission (ILC)8,
the International Court of Justice (ICJ)9 as well as arbitral tribunals themselves.10 Put
differently, while it remains the task of the arbitral tribunal to decide a case and interpret
and apply an IIA to this end, the contracting States retain the power to clarify the
language/meaning of a treaty through an authoritative interpretation.

Therefore, although tribunals and contracting States play different roles in the
interpretation of IIAs, they share interpretive authority. Interpreting IIAs is hence not a
monologue by tribunals, but could be understood as a “constructive dialogue between
investment tribunals and treaty parties”.11 However, until present, States have largely
neglected their role in interpreting IIAs. Instead, they left the task of giving meaning
to treaty provisions solely to arbitral tribunals. Yet, rising concerns among States
and other stakeholders demonstrate the challenges of an overly wide discretion of
arbitrators coupled with the often broad and imprecise language of IIAs.

2) Lack of predictability in current IIA
interpretation by tribunals

There are a number of issues that raise concerns about the legal predictability of IIAs
in ISDS proceedings. One relates to divergent interpretations of identically or similarly
worded treaty obligations. For example, in response to its economic crisis in 2001,
Argentina enacted a number of measures that were later challenged in investment
proceedings, in the course of which tribunals and subsequent ICSID ad hoc Committees
disagreed on the proper reading of the scope and content of Argentina’s necessity
defense pursuant to Article XI of the Argentina-United States Bilateral Investment
Treaty (BIT) and its relationship to customary rules on State responsibility.12

Furthermore arbitral tribunals have not always rigorously followed general international
rules of treaty interpretation and produced poorly reasoned awards. In 2008, Fauchald
found that “only in exceptional decisions did tribunals integrate the VCLT into their

6 See for more detail Arsanjani, Mahnoush H./ Reisman, W. Michael, «Interpreting Treaties for the Benefit of Third Parties:
The “Salvors’ Doctrine” and the Use of Legislative History in Investment Treaties» Editorial Comment, American Journal of
International Law, Vol. 104, No. 1, 2010, p. 598.

7 Permanent Court of International Justice, Jaworzina, Advisory Opinion, 1923, P.C.I.J., Series B, No. 8, p. 37.
8 Yearbook of the International Law Commission, 1966, Vol. II, p. 221, para. 14.
9 International Court of Justice in the Kasikili/Sedudu Island (Botswana/Namibia), Judgement (13 December 1999), para. 63.
10 See for example ADF Group Inc. v. United States, ICSID No. ARB(AF)/00/1 (9 January 2003), para. 177.
11 Roberts, Anthea, «Power and Persuasion in Investment Treaty Interpretation: The Dual Role of States», American Journal

of International Law, Vol. 104, No. 1, 2010, p. 225.
12 For instance CMS v. Argentina, Award, ICSID Case No. ARB/01/8 (12 May 2005); Enron v. Argentina, ICSID, Award,

Case No. ARB/01/3 (22 May 2007); LG&E v Argentina, Decision on Liability, ICSID Case No. ARB/02/1 (3 October 2006);
Sempra v. Argentina, Annulment Decision, ICSID Case No. ARB/02/16 (29 June 2010); Enron v. Argentina, Annulment
Decision, ICSID Case No. ARB/01/3 (30 July 2010).


reasoning beyond general references.”13 In 2010 Arsanjani and Reisman criticized the
improper use of the travaux préperatoires by tribunals.14 The use and application of
interpretation rules, however, is an essential element of an arbitral tribunal's mission to
produce a well reasoned decision.

Finally, some arbitral awards fail to interpret IIAs in a manner giving due consideration
to the balance of rights and obligations. The tribunal in SGS v. Philippines, for instance,
found that it is “legitimate to resolve uncertainties in [the IIA’s] interpretation so as to
favor the protection of covered investments”.15 Failing to pay due regard to legitimate
considerations other than investment protection, however, curtails the State’s
regulatory autonomy to the detriment of sustainable development. Along these lines,
the tribunal in Noble Ventures v. Romania stated, “it is not permissible, as is too often
done regarding BITs, to interpret clauses exclusively in favor of investors”.16

In sum, deficiencies in the interpretive process with potentially negative consequences
for public policy making merit attention by States. While ideally tribunals should
employ international rules of treaty interpretation rigorously producing solidly reasoned
awards, and make ISDS more consistent, predictable and legitimate, States can play
an important role in fostering such outcome.

3) Greater involvement of States in interpretation
and potential limitations of such an approach

State involvement in interpretation can help guide tribunals in their reading of IIAs,
enhancing, amongst others, the predictability of awards. It also proactively clarifies the
protective scope of investment treaties for investors and can thus prevent disputes.
Moreover, interpretation may be a way to strengthen the public policy dimensions of
existing IIAs. For instance, in the context of a recent claim against Australia’s plain
packaging legislation on tobacco products, it has been suggested that Hong Kong and
Australia as contracting parties to the IIA forming the basis of the claim could clarify
the meaning of certain treaty provisions to ensure that investment protection does not
trump broader public health objectives. It has also been suggested in this regard that
an interpretation of the BIT could have retrospective effect and might be relevant for
determining the current claim.17

While so far, States have rarely given interpretive guidance, this can play an important
part in determining the extent of States’ commitments under IIAs and to ensure that
IIAs reflect the underlying public policy considerations. Compared to complicated
and time consuming treaty re-negotiation, modification or denunciation, interpretation
may be an efficient option to improve predictability of awards. Interpretive instruments
can thus complement better treaty language and other current efforts to remedy the
challenges posed by today’s IIA regime.

At the same time, State involvement in the interpretation of IIAs can be controversial.
Hence, a number of potential limitations need to be considered.

First, States play a dual role in investment law. On the one hand, they are the contracting
parties and masters of their IIAs. In that capacity States may provide authentic and
authoritative interpretations of their treaties.18 On the other hand, States may also
be respondents in specific ISDS proceedings. Hence, States could potentially use
interpretive instruments to influence litigation of ongoing cases to their benefit, raising
questions about the equality of arms between the disputing parties. To avoid concerns
on abusive interpretations, States may want to issue interpretive statements proactively
– in advance – and outside of a particular dispute. However, as the experience from

13 Ole Kristian Fauchald, «The Legal Reasoning of ICSID Tribunals – An Empirical Analysis», European Journal of International
Law, Vol. 19, No. 2, 2008, p. 314.

14 Arsanjani/ Reisman, supra note 6, p. 597.
15 SGS v. Philippines, ICSID Case No. ARB/02/6, Decision on Jurisdiction (29 January 2004), para. 116.
16 Noble Ventures, Inc. and Romania, ICSID Case No. ARB/01/11, Award, (12 October 2005), para. 52.
17 Tania Voon and Andrew Mitchell, «Time to quit? Assessing International Investment Claims against Plain Tobacco Packaging

in Australia», Journal of International Economic Law, Vol. 14, No. 3, 2011, p. 529.
18 See supra note 7-10.


NAFTA’s Free Trade Commission’s interpretation shows (infra Box 3), even in ongoing
proceedings, tribunals have deferred to the interpretations of the contracting States.

Second, unlike most other international treaties in the economic area, IIAs create
rights for individuals. These rights of foreign investors and the legitimate expectations
arising thereof could potentially be compromised by subsequent authoritative
interpretations by the contracting States. Yet, treaties are not set in stone. States
retain the authority to modify or even terminate the IIAs that give rise to investor rights.
Similarly investors have to accept that their rights deriving from a treaty may be clarified
through subsequent interpretive statements. In any case, legitimate expectations do
not protect a specific reading of an IIA provision to the exclusion of other reasonable

Third, the interpretation of IIAs has to be distinguished from treaty amendments.
Interpretation is in principle confined to clarifying the terms of a treaty and not aimed
at filling them with a new meaning. In contrast, amendments may add to or modify
existing obligations and they typically require formal adoption, for example, through
domestic ratification. In practice, however, the borderline between interpretation and
amendment may be blurred.19 Indeed, international courts and tribunals in the past
have accepted interpretations amounting to a de facto amendment.20 It must be noted
that such State practice may be highly controversial.

Despite these potential limitations, State involvement in interpretation may, under
certain circumstances, offer an efficient and attractive option for States.

III. Interpretation Rules as a Roadmap for State

1) Interpretation rules under public international law
Interpretation of public international law treaties follows a specific canon of interpretation
rules. The most important and widely used canon of interpretation rules is found in
Articles 31 and 32 of the Vienna Convention on the Law of Treaties (VCLT) (see Box
1). These rules establish the elements interpreters must take into account when giving
meaning to treaty provisions and how to prioritize amongst the different elements.21
The Convention constitutes a codification of international customary rules on treaty
interpretation relevant to all States.22 In consequence, arbitral tribunals are required
to apply the VCLT rules irrespective of whether the contracting States have ratified
the VCLT or whether an IIA explicitly provides for the VCLT’s application. The rules of
interpretation in the VCLT are extensively used by international adjudicating bodies
such as the ICJ, panels and the Appellate Body of the World Trade Organization (WTO),
and international criminal courts and tribunals.

The VCLT embodies three main approaches to treaty interpretation. Article 31 of the VCLT
contains elements of (i) the “textual” school which places emphasis on the “ordinary
meaning of the word” and (ii) the “teleological” school which refers to the object and
purpose of a treaty. Article 32 partly reflects (iii) the historical “original intention of the
parties” approach, but only serves as a supplementary means of treaty interpretation.
The primary interpretation rules in Article 31, however, are not hierarchical. They are
to be used in a single “holistic exercise” giving weight to all of Article 31’s elements
(not only the “ordinary meaning”).23 If applied rigorously, the VCLT interpretation rules
ensure high legal security and predictability.

19 Roberts, Anthea, «Power and Persuasion in Investment Treaty Interpretation: The Dual Role of States», American Journal
of International Law, Vol. 104, No. 1, 2010, pp. 201-202.

20 For example, Legal Consequences for States of the Continued Presence of South Africa in Namibia (South West Africa)
Notwithstanding Security Council Resolution 276 (1970), Advisory Opinion (21 June 1971), para. 22. Case concerning
the Dispute Regarding Navigational and Related Rights (Costa Rica v. Nicaragua), Judgment of the International Court of
Justice (13 July 2009), para. 64,

21 VCLT Article 31(1) begins with «A treaty shall be interpreted...» (emphasis added).
22 Gardiner, Richard K.,Treaty Interpretation (New York: Oxford University Press), 2008, pp. 12ff.
23 WTO Appellate Body Report, European Communities – Customs Classification of Frozen Boneless Chicken Cuts (EC –

Chicken Cuts), WT/DS269/AB/R, WT/DS286/AB/R, at para. 176. See also Yearbook of the International Law Commission,
1966, Vol. II, at 219–220.


The VCLT does not entail an exhaustive list of interpretive techniques. Other interpretive
rules may be implicitly contained in the VCLT rules, such as the principle of effective
interpretation.24 Some interpretive techniques are not mentioned in the VCLT at all, such
as in dubio mitius (principle of restrictive interpretation), expressio unius est exclusio
alterius (express mention of one thing excludes all others) or the eiusdem generis (of
the same kind) approach.25 The status of the latter group of principles, however, is
subject to some debate. Hence, whereas the VCLT may not be exhaustive, it is the
most widely accepted set of interpretation rules.

2) Interpretation of IIAs – different stages,
different tools

The life of an IIA is characterized by different stages from its drafting over its
implementation to its potential application by international arbitral tribunals. At each of
these stages, interpretation and tools to guide it play a different role (figure 1).

In the treaty negotiating process, the drafters need to anticipate future interpretations
with farsighted and precise treaty language and clear interpretation guidelines. Once
the treaty is concluded, the contracting States can clarify the treaty language by issuing
interpretive statements and agreements. In addition, States may intervene in dispute
settlement proceedings. Furthermore, after the dispute has been decided States can
scrutinize arbitral awards and comment on the interpretation by tribunals. Therefore, at
every stage States have different interpretive tools at their disposal.

24 Yearbook of the International Law Commission, 1966, Vol. II, p. 218.
25 See for instance Schreuer, Christoph, «Diversity and Harmonization of Treaty Interpretation in Investment Arbitration,» in

Olufemi Elias, Malgosia Fitzmaurice, and Panos Merkouris (eds.), Treaty Interpretation and the Vienna Convention on the
Law of Treaties: 30 Years On (Leiden: Martinus Nijhoff Publishers, 2010), pp. 129-151.

Box 1. Articles 31 and 32 of the Vienna Convention on the Law of Treaties

Articles 31 and 32 codify customary rules of treaty interpretation. Article 31 contains three
main elements. The first paragraph underlines the importance of the careful wording of a
treaty. It states that treaty terms should be interpreted in accordance with their ordinary
meaning and in light of their object and purpose.

The second paragraph of Article 31 refers to the “context of a treaty.” This comprises
its “text including its preamble and annexes” as well as “any agreement” or “any
instrument” accepted by both parties and made in conclusion with the treaty. Hence, by
concluding side-agreements, protocols, understandings and other instruments together
with the treaty, contracting States can guide tribunals regarding the object and purpose
of specific IIA provisions.

The third paragraph of Article 31 deals with the subsequent application of a treaty that
may provide further “context” for the interpretation. This includes (a) any subsequent
agreement, (b) any subsequent practice establishing agreement between the contracting
parties regarding the treaty’s interpretation, and (c) any relevant rules of international
law applicable between the parties. Therefore, both the evolving practice between the
contracting parties as well as the development of the general system of international law
applicable to the parties can affect interpretation.

Finally, Article 32 concerns supplementary means of treaty interpretation. This includes
but is not limited to the travaux préperatoires of the treaty. They may be relevant “to confirm
the meaning resulting from an application of Article 31, or to determine the meaning when
the interpretation according to Article 31 (a) leaves the meaning ambiguous, or obscure or
(b) leads to a result which is manifestly absurd or unreasonable”. In these circumstances,
the travaux préperatoires or any other supplementary means, including even unilateral
instruments, may provide helpful guidance for the interpretation of a treaty.

Source: UNCTAD.



IIA Drafting IIA Conclusion

VCLT Art 31(1)

•Object and


VCLT Art 31(2)
• Instrument or

adopted at IIA

IIA in Force

This sequenced approach is supported by the Vienna Convention. The VCLT
interpretation rules themselves reflect a distinction between different stages and
different tools. In other words, the VCLT provides a roadmap for stage-specific State

3) Interpretation of IIAs: joint and
unilateral approaches

IIAs are a product of at least two State parties. In addition to multilateral tools (see Box
2), interpretative tools can accordingly originate from one or several (at least two) State

Joint acts and statements by the contracting parties are considered to be reflective of
the intention of all States concerned and, as such, they must be treated as authoritative
by subsequent arbitral tribunals.26 Any agreement or accepted practice, regardless of
its legal form27 (e.g. a joint declaration, an exchange of letters or even verbal notes),28
establishing consent between the contracting parties as to a treaty’s interpretation is
to be considered as authoritative.29 This is reflected in the VCLT rules Article 31(2) and
(3)(a) and (b).

In addition, some unilateral instruments are available to States such as ratification
documents or declarations.30 States cannot unilaterally give authoritative meaning to
treaty terms. However, in the absence of conclusive joint interpretations some unilateral
documents or statements may provide guidance to arbitrators as supplementary
means of treaty interpretation under VCLT Article 32.

26 See supra note 7-10.
27 Judgment of the International Court of Justice in the Kasikili/Sedudu Island (Botswana/Namibia), Judgement (13 December

1999), I.C.J. Reports 1999, p. 1045, para. 49.
28 See Gruslin v. Malaysia, Award, ICSID Case No. ARB/99/3 (27 November 2000), para. 23.4.
29 Gardiner, Richard K. Treaty Interpretation (New York : Oxford University Press), 2008, pp. 216–220. See also Yearbook of

the International Law Commission, 1999, Vol. II, UN Doc. A/CN.4/SER.A/1999/Add.l (Part 2) p. 125, Rule 1.5.3.
30 See Section IV 2)-5) below.

Figure 1. The VCLT is guiding interpretation at every stage in the
lifespan of an IIA



VCLT Art 31(3)
•Subsequent agreement
•Subsequent practice
•Other rules of international law

applicalbe between the parties

VCLTArt32•Supplementary means of treaty interpretation



Some interpretive tools are only available if the contracting parties explicitly provide for
them in their IIAs. Examples for such IIA specific interpretive mechanisms are treaty-
based institutions such as the NAFTA Free Trade Commission or the renvoi procedure
giving the tribunal the option to send certain questions back to the contracting parties
for interpretation.31

IV. Interpretive Instruments of the Contracting

1) Drafting of IIAs
During negotiations, drafters need to consider how a treaty provision may be interpreted
in the future. Accordingly, States can provide a clear roadmap for future interpreters
both in terms of substance and procedure.

Precise wording of treaty provisions

Many IIA provisions are loosely phrased. Recently, however, the drafting of IIAs has
gradually gained in precision. In part, this has been prompted by the increase of ISDS
proceedings coupled with the States’ desire to reduce the margin of discretion for
tribunals’ interpretation.32 Farsighted and precise drafting thus plays a crucial role in
delineating the discretion of future interpreters hence fostering greater predictability.

One option for negotiators to increase the precision of treaty terms is to supplement
broad standards with specific clarifications. Some recent formulations of the provisions
on most-favoured-nation treatment (MFN), fair and equitable treatment (FET) and
expropriation are illustrative of this trend.33 Another, related way to avoid tribunals giving
broader than intended meaning to certain treaty terms is to include an exhaustive or
a negative list. For instance the Canada-Peru BIT (2007) in Article 1 excludes from
the definition of “investment” specific assets such as trade financing transactions.34

Hence, clarity can be enhanced in two ways: (i) by specifying what the treaty obligation
entails35 and (ii) by delineating what is not covered.36

Reference to rules of treaty interpretation

Governments may also want to clearly state the rules to be followed when interpreting
a treaty.

While the VCLT rules apply by default, their inclusion into IIAs through reference may
be useful to ensure their rigorous application by arbitral tribunals.

The Australia-United States FTA (AUSFTA), for example, provides in Article 21.9 (2)
that a panel should “consider this Agreement in accordance with applicable rules of
interpretation under international law as reflected in Articles 31 and 32 of the Vienna
Convention on the Law of Treaties (1969).” 37 Recognizing that the AUSFTA does not
have investor-State, but only State-to-State dispute settlement, policy makers may

31 See Section IV 3) and 4) below.
32 UNCTAD, Bilateral Investment Treaties 1995-2006: Trends in Investment Rulemaking (United Nations, New York and

Geneva, 2007), at p. 30.
33 For a detailed analysis of these provisions consult the UNCTAD Series on Issues in International Investment Agreements

(A Sequel) on Most-Favoured Nations Treatment (Fair and Equitable Treatment and Expropriation forthcoming) available at

34 See UNCTAD Series on Issues on International Investment Agreements (A Sequel) on Scope and Definition, available at:

35 Examples include i) listing the type of assets covered by an IIA’s scope and definition clause, ii) specifying the type of
government action that is prohibited by a particular clause, or iii) defining the extent of coverage of the MFN clause.

36 Examples include i) specifying the type of assets are not covered by an IIA’s scope and definition clause; ii) clarifying the
type of government action that is not prohibited (e.g. regulatory takings), or iii) stating that the MFN clause does not apply
to ISDS.

37 Similar language, referring to customary rules of interpretation of public international law, is used in the WTO Dispute
Settlement Understanding Article 3.2 and in many FTAs with investment chapters such as Article 190 (3) China-New
Zealand FTA.


still wish to consider including such language also in the context of investor-State

Contracting parties can also include autonomous interpretation standards in their IIAs
corresponding to the specific needs of the investment law regime supplementing or
substituting the VCLT rules. They may refer to separate interpretive principles such as
in dubio mitius or devise treaty specific canons of interpretation to be followed.38

Reference to other fields of international law

Given the increasing overlap and interaction between the international investment
regime and other fields of international law such as the WTO Agreements and treaties
relating to the protection of the environment, public health, and human rights, IIAs
should not be considered in isolation.

In an effort to achieve coherence between IIAs and the wider spectrum of public
international law, some treaties suggest that the interpretation of provisions shall
be compatible with other rules of international law. This facilitates the “systemic
interpretation” approach in Article 31 3(c) of the VCLT that takes into account other
relevant rules of international law applicable between the parties. One step in that
direction is the Belgium-Togo BIT (2009) in Article 11 (3) that contains a specific
reference to Multilateral Environmental Agreements (MEAs): “The Contracting Parties
reaffirm their commitments under the international environmental agreements, which
they have accepted.”

Non-economic treaty objectives in the preamble

VCLT Article 31(1) provides that a treaty provision has to be interpreted in light of its
“context” and “object and purpose”. An agreement’s preamble forms part of its “context”
and typically states the objectives of the agreement. Many preambles in IIAs refer to the
protection of investments as the sole object and purpose of the treaty. This has led
some tribunals to adopt an interpretation focusing primarily on investors’ interests.39
States can prevent such an occurrence by clearly stipulating that investment protection
is not an end in itself. Instead it should serve as a means to facilitate sustainable
development and reaffirm a State's right to regulate in the public interest.

38 Noting that it is not an IIA, the WTO Anti-Dumping Agreement, for instance, reads in Article 17.6 "the panel shall interpret
the relevant provisions of the Agreement in accordance with customary rules of interpretation of public international law.
Where the panel finds that a relevant provision of the Agreement admits of more than one permissible interpretation, the
panel shall find the authorities’ measure to be in conformity with the Agreement if it rests upon one of those permissible

39 See supra note 15 and 16.

Box 2. Multilateral instruments

Beyond unilateral and bilateral interpretive instruments, multilateral approaches
to interpretation can also play a role in fostering a coherent and predictable
reading of IIAs. This is particularly useful when it comes to addressing global
challenges such as climate change and problems common to the investment
regime as a whole. For example, one could consider a multilateral declaration on
the relationship between IIAs and the climate change regime clarifying that IIAs
do not constrain climate change measures and ensure that investment treaties
are read in line with the related multilaterally agreed global policies.a

A process of multilateral consensus building can be a starting point to formulate
new multilateral solutions e.g. for clarifying the scope of core IIA obligations or
shedding light on the relationship between IIAs and other fields of international
law. Such a process may result in multilateral interpretive tools taking different
forms ranging from soft law instruments, such as guidelines and interpretive
principles for arbitrators, to hard legal instruments.

a UNCTAD, World Investment Report 2010: Investing in a Low-Carbon Economy (United Nations, New
York and Geneva, 2010), pp. 138, 147 (available at www.unctad.org/en/docs/wir2010_en.pdf).


For instance, in the preamble of their 2005 FTA, India and Singapore recall “their right
to pursue economic philosophies suited to their development goals and their right to
regulate activities to realize their national policy objectives.”

In general, States have already used the preamble of their IIAs to reaffirm regulatory
flexibilities (such as their right to regulate),40 to reiterate their commitment to human
rights, labour or environmental standards,41 or to promote other policy objectives (such
as sustainable development and transfer of technology).42

2) Conclusion of an IIA
At the conclusion of an IIA, contracting States can adopt additional instruments such
as side-agreements, protocols, understandings or exchanges of letters. In addition, a
number of unilateral tools may be open to governments and parliaments at the moment
of concluding IIAs.

A. Joint instruments

Formal side-agreements

An illustrative example of a joint side-instrument is the FTA practice of Canada and
the United States. Instead of including extensive environmental and labour standards
in their agreements, these countries sign so-called side-agreements to their FTAs,
addressing these issues specifically.43 These side-agreements form part of the IIA's
"context" for interpretation pursuant to VCLT Article 31(2). Other examples, more
common with bilateral treaties, are protocols signed together with IIAs. These protocols
sometimes also constitute an integral part of the original IIA, as is the case for the
China-Finland BIT (2004),44 and hence influence the interpretation of the rights and
obligations set out in the IIA.

Informal side-instruments

While the instruments above create direct legal obligations between the contracting
States, other informal instruments that are agreed upon at the conclusion of the treaty
can also inform the interpretation of IIAs as part of its “context”. The letter exchange
between the United States Trade Representative and the Moroccan Minister Delegate
for Foreign Affairs and Cooperation at the conclusion of the Morocco-United States
FTA, for instance, clarifies the scope of the labour and environmental provisions of that
treaty,45 and in so doing, guides a tribunal’s interpretation of the rights and obligations
established in the IIA.

B. Unilateral instruments

Statements and documents in the course of the ratification process

Not only international instruments play a role in treaty interpretation, but also purely
national statements may be of relevance. This is especially the case if they are made
during the course of the ratification process. Letters and memorials to government or
legislature, commentaries, official statements and parliamentary debate may shed light
on the meaning of IIA provisions. As the tribunal in Mondev International Ltd. v. United
States stated: “[E]xplanations given by a signatory government to its own legislature in

40 India-Singapore FTA, preamble (2005); Panama-Taiwan FTA, preamble (2003).
41 United States-Uruguay BIT, preamble (2005); CARIFORUM-EC Economic Partnership Agreement, preamble (2008).
42 ASEAN-China Agreement on Investment (2009) preamble; CARIFORUM-EC Economic Partnership Agreement, preamble

43 For instance, the Canada-Panama FTA, signed on 14 May 2010, is supplemented by two side agreements on labour and

the environment. Side agreements were also concluded in connection with NAFTA.
44 Protocol to the Agreement on the Encouragement and Reciprocal Protection of Investments between the Republic of

Finland and the People’s Republic of China, signed on 15 November 2004.
45 Letter by Catherine A. Novelli, Assistant United States Trade Representative for Europe and the Mediterranean to the

Honorable Taïb Fassi Fihri, Minister Delegate for Foreign Affairs and Cooperation, Kingdom of Morocco, Washington, D.C.,
June 15, 2004, available at http://www.moroccousafta.com/pdf/letter-labor-env.pdf.


the course of ratification or implementation of a treaty […] can certainly shed light on
the purposes and approaches taken to the treaty.”46

3) Subsequent agreements and practice - clarifying
existing IIAs

A. Joint instruments

Ad-hoc authoritative interpretation by contracting parties

State parties may clarify the content of their original treaty commitments through
subsequent practice or agreement. This possibility follows from VCLT Article 31 (3) (a)
and (b).

Two points made above must be reiterated. First, a joint interpretation may be
authoritative irrespective of its legal form.47 However, it is important that the document
or letter exchange not merely implies but clearly establishes a common understanding
in order to qualify as agreement between the contracting parties. Similarly, concordant
practice requires at least a tacit acceptance of an interpretation by all parties.48
Second, by virtue of general international law contracting parties can provide a joint
interpretation of the IIA regardless of whether the treaty expressly authorizes them to
do so.49

Some IIAs, however, expressly address the issue of authoritative interpretations.
For instance, Article X (6) of the Canada-Czech Republic BIT (2009) provides: “An
interpretation of this Agreement agreed between the Contracting Parties shall be binding
on a Tribunal established under this Article.” Some treaties provide for “consultations”
to be proposed by each party to the treaty and on any matter concerning interpretation.
An example of this can be found in the Ghana-Netherlands BIT (1989) Article 12: “Either
Contracting Party may propose the other Party to consult on any matter concerning the
interpretation or application of the Agreement. The other Party shall accord sympathetic
consideration to and shall afford adequate opportunity for such consultation.”

Consultations were used in CME v. Czech Republic to arrive at a common position
between the Dutch and Czech Governments with regard to the BIT’s interpretation.50
The tribunal used this joint act to support its findings.51

Interpretation by IIA institutions

In addition to ad-hoc mechanisms, a number of IIAs establish institutionalized
cooperation between the contracting States. These commissions or committees
consist of representatives from the State parties and are charged with the task of
monitoring the implementation of the treaty and issuing interpretive statements on
treaty provisions. The existence of such standing bodies facilitates the exchange of
views and the formulation of common interpretations.

46 Mondev Int’l Ltd. v. United States, ICSID No. ARB(AF)/99/2 (Oct. 11 2002), para. 111. See also: CMS Gas Transmission
Co. v. Argentina, ICSID No. ARB/01/08 (May 12 2005), paras. 362, 369; Generation Ukraine Inc. v. Ukraine, ICSID No.
ARB/00/9 (Sept. 16 2003), paras. 15.4 –15.7; CMS Gas Transmission Co. v. Argentina, ICSID No. ARB/01/08, Jurisdiction
(July 17, 2003), para. 82; Bayview Irrigation District et al. v. Mexico, ICSID Case No. ARB(AF)/05/l, Award (19 June 2007),

47 See supra note 26.
48 Aust, Anthony, Modern Treaty Law and Practice (Cambridge University Press, 2007), pp. 231-243. Proving the existence of

a joint interpretation can hence be very fact-intensive. In a number of arbitral proceedings, the tribunals rejected documents
presented by the respondent State on the premise that they did not establish an explicit agreement or a concordant
practice between the contracting parties. See also discussion in Newcombe, Andrew Paul/Paradell, Lluis, Law and
Practice of Investment Treaties: Standards of Treatment (Kluwer Law International, 2009), pp. 117-119.

49 The International Law Commission provides that «The interpretation resulting from an interpretative declaration made in
respect of a bilateral treaty by a State or an international organization party to the treaty and accepted by the other party
constitutes the authentic interpretation of that treaty.» Yearbook of the International Law Commission, 1999, Vol. II, UN Doc.
A/CN.4/SER.A/1999/Add.l (Part 2) p. 125, Rule 1.5.3.

50 CME Czech Republic B.V. v. Czech Republic, Final Award (UNCITRAL, 14 March 2003), paras. 87-93.
51 Ibid. paras. 400, 437, 504.


For instance, Article 165 of the Japan-Mexico FTA (2004) provides for the creation
of a Joint Committee to serve as a forum for consultations to review and implement
the FTA, adopt interpretations of the FTA, and decide on the rules of procedure for
arbitration. The role of such commissions or committees has already been tested in the
context of NAFTA (see Box 3).

Release of travaux préparatoires

VCLT Article 32 considers the travaux préparatoires to be a merely supplementary
means of treaty interpretation. Nonetheless, arbitrators may resort to these documents
to confirm a particular interpretation reached on the basis of primary interpretive tools, or
to clarify an ambiguous term. Especially in the latter case, the travaux préparatoires may
guide tribunals to the authentic reading among competing reasonable interpretations.
In that sense, the release of travaux préparatoires may be a means for countries to
ensure that their original intent is preserved. To this end, for instance, the NAFTA Parties
have released negotiating texts of NAFTA’s investment chapter.52

B. Unilateral instruments

Unilateral documents and declarations

A State can unilaterally publish or release documents which are indicative of its
negotiating position, which can assist arbitrators in the interpretation of treaty terms.
For example, States may release letters that reflect their interpretation of terms of the
IIA as of the time of its negotiation. In some cases unilateral acts may also constitute the
first step towards a joint interpretation between the parties.53 If the other contracting
parties endorse or acquiesce to a unilateral interpretive declaration, this may indicate
subsequent practice.54

Model IIAs

Model IIAs can provide guidance to arbitral tribunals and facilitate an evolutionary
reading of IIAs, especially if they are publicly available and supplemented by an
official commentary.55 Amongst several other functions, model IIAs mirror a country’s
investment policy approach.56 They are periodically reviewed, either to adjust to new
policy priorities, or to respond to the need for clarifying the content of IIAs.

4) Dispute intervention by States
In response to the increased awareness among States on ISDS claims, a growing
number of mechanisms for unilateral or joint State intervention in investment disputes
have found their way into IIAs.

A. Joint instruments

Renvoi of an interpretation issue back to the Parties

A mechanism introduced by recent treaties is the renvoi of certain questions, which
are explicitly defined in the treaty, to the State parties for interpretation. In these cases,
the treaty provides that the contracting parties (or sometimes the specifically created
joint Commission or Committee) shall interpret certain matters or provisions and issue

52 Available at http://www.naftaclaims.com/commission.htm. However, a comprehensive compilation of the travaux
préperatoires of NAFTA, including negotiation minutes, is not yet publicly available.

53 It must be noted, however, that the weight given to unilateral acts may differ. In the past, arbitral tribunals have been
reluctant to accept arguments made in the context of an ISDS proceedings by one contracting party and later endorsed
by the other contracting party as a respondent in a subsequent proceeding as evidence for concordant practice. See for
instance Gas Natural SDG SA v Argentina, Decision on Jurisdiction, ICSID Case No. ARB/03/10 (17 June 2005), para. 47,
footnote 12.

54 See Roberts, Anthea, «Power and Persuasion in Investment Treaty Interpretation: The Dual Role of States», American
Journal of International Law, Vol. 104, No. 1, 2010, p. 200, in particular footnotes 101,102.

55 UNCTAD, World Investment Report 2010: Investing in a Low-Carbon Economy (United Nations, New York and Geneva,
2010), p. 85, available at www.unctad.org/en/docs/wir2010_en.pdf.

56 “Model IIAs”, UNCTAD Yellow Series, forthcoming.


Box 3. Lessons from the NAFTA Free Trade Commission’s interpretation

The NAFTA Free Trade Commission (FTC), a body of cabinet level officials from each of
NAFTA’s signatories established under the treaty, is authorized to issue interpretations
binding on tribunals established under NAFTA’s investment chapter.a In July 2001, the
FTC issued its only interpretation to date concerning, among others, the minimum
standard of treatment in NAFTA Article 1105(1). The Commission clarified that the
provision refers to the customary international law minimum standard and that the
obligations of “fair and equitable treatment” and “full protection and security” do not
mandate a treatment beyond this minimum standard.b

At the time when the FTC issued this interpretation multiple arbitrations were ongoing.c
Pope & Talbot v. Canada and ADF Group, Inc. v. U.S., are two examples that illustrate
how tribunals reacted to the FTC’s interpretation. They addressed possible challenges
for ongoing proceedings arising out of such State intervention, in particular, with regard
to due process and whether these interpretations amounted to a de facto amendment
of NAFTA itself.

The tribunal in Pope & Talbot had already issued an interim award on the merits
before the FTC interpretation was made. Faced with the prospect of applying the
interpretation retroactively to an already issued decision, the Pope & Talbot Tribunal
was concerned with due process considerations. It initiated a letter exchange with
Canada and the other NAFTA Parties to explore how the FTC’s statements were
compatible with basic standards of fairness. Although the Tribunal was sympathetic
to the claimant’s argument that the interpretation constituted a de facto amendment
of NAFTA, it eventually accepted the FTC interpretation as such. However, this
conclusion did not disturb the Tribunal’s findings with respect to Canada’s NAFTA
violations, and accordingly, the Tribunal did not have to make a decision on the validity
of an interpretation that would retroactively reverse a prior ruling.

In contrast to the reaction of the tribunal in Pope & Talbot, the tribunal in ADF Group,
Inc. v. U.S. accepted the FTC interpretation readily stating “[n]o more authentic and
authoritative instruction on what the parties intended to convey in a particular provision
of NAFTA, is possible.” With respect to the issue of a de facto amendment of NAFTA,
the ADF Tribunal explicitly accepted the FTC statement as an interpretation on the
grounds that “[n]o document purporting to be an amendment has been submitted by
either the Respondent or the other NAFTA Parties”.

In both cases the tribunals addressed the issues differently, but essentially reached
the same conclusions. Namely, that the FTC interpretation is binding and does not
amount to a formal amendment to NAFTA. Subsequent tribunals have followed this
lead. Yet, as for instance the recent Merrill & Ring Forestry v. Canada pointed out, the
impact of the FTC interpretation only provided limited guidance since uncertainties as
to the current scope of customary international law remain.

a See, NAFTA, Arts. 1131(2), 2001(1) & 2(c).
b NAFTA Free Trade Commission, Notes of Interpretation of Certain Chap. 11 Provisions (31 July 2001)

available at http://www.international.gc.ca/trade-agreements-accords-commerciaux/disp-diff/nafta-interpr.

c See, e.g., Mondev International Ltd. v. United States of America, ICSID Case No. ARB(AF)/99/2, Award, paras.
100-125, 11 October 2002; Loewen Group, Inc. and Raymond L. Loewen v. United States, ICSID Case No.
ARB(AF)/98/3, Award on Merits, paras. 125-128, 26 June 2003; Methanex v. United States, UNCITRAL.


a binding interpretation on the tribunal. Failing agreement between the parties, the
tribunal regains the ability to interpret the relevant provisions.

The Japan-Mexico FTA (2004) provides an example:

“[w]here a disputing Party asserts as a defense that the measure alleged to be a breach
is within the scope of a reservation or exception set out in Annex 6, Annex 7, Annex 8
or Annex 9, on request of the disputing Party, the Tribunal shall request the Joint
Committee to adopt an interpretation on the issue. The Joint Committee, within
60 days of delivery of the request, shall adopt an interpretation and submit in writing
its interpretation to the Tribunal.

An interpretation adopted and submitted under paragraph 1 above shall be binding on
the Tribunal. If the Joint Committee fails to submit an interpretation within 60 days, the
Tribunal shall decide the issue.” (Article 89, emphasis added)

A similar provision can be found in Article 31 of the United States-Uruguay BIT (2005).
In that context, no institutional set-up exists so that the renvoi is addressed directly to
the contracting parties.

Consultation of draft award

Certain IIAs, like the Colombia-Peru BIT (2007) in Article 25 (14)a) provide that, before
issuing a decision, any disputing party can request the tribunal to send the draft award
for comments to the disputing parties and the non-disputing State party to the treaty.
All State parties have 60 days to provide comments. The tribunal shall consider these
comments and issue its decision within 45 days from receipt of the parties’ comments.

B. Unilateral instruments

Intervention by the non-disputing State

Some treaties explicitly provide for the intervention by the other, non-disputing State
party or parties into the arbitral proceedings.

For example, the non-disputing State (or States) may make submissions to a tribunal
regarding questions of interpretation of the agreement. Article 35(1) of the Canada-Peru
BIT (2006) for example provides that: “On written notice to the disputing parties, the
non-disputing Party may make submissions to a Tribunal on a question of interpretation
of this Agreement.” Similarly, NAFTA also allows for the intervention of the other State
Party in accordance with its Article 1128.57

However, even when a treaty does not explicitly provide for this mechanism, tribunals
are likely to pay attention to statements made by the non-disputing State party in order
to find confirmation of subsequent agreement or practice between the contracting
parties.58 When all of the non-disputing treaty parties intervene in support of the reading
proposed by the respondent State, this amounts to an authoritative interpretation.

Expert advice: calling on the original negotiators

One instrument available to a disputing State party is to call upon the expert advice of
original negotiators from both Contracting Parties to clarify an issue of interpretation.
In Tza Yap Shum v Peru Chinese and Peruvian BIT treaty negotiators were invited to
give evidence before the tribunal. The arbitrators considered their statements as proof
to the effect that the contracting parties did not contemplate the MFN clause to extend
to dispute settlement matters.59

57 See, for example Submission of United States of America regarding the relationship of the MFN and FET provision in the
NAFTA dispute Chemtura Corporation v Canada, available at http://www.state.gov/documents/organization/128849.pdf.

58 This was done, for instance, in Aguas del Tunari, S.A. v. Republic of Bolivia, ICSID Case No. ARB/02/3, Decision on
Respondent’s Objections to Jurisdiction (21 October 2005), paras. 249-263. However, the tribunal did not find a subsequent
practice or agreement.

59 Tza Yap Shum v. Republic of Peru, ICSID Case No. ARB/07/6, Decision on Jurisdiction and Competence (19 June 2009),
paras. 210-212.


5) Post-dispute phase
The post-dispute phase provides an opportunity for States to react to interpretations in
arbitral awards. Done either unilaterally or jointly, the contracting parties can carefully
examine the reasoning of arbitrators and endorse or reject particular interpretations.
By publishing these evaluations, either in print or on their websites, treaty parties may
provide guidance for future tribunals.

In Société Générale de Surveillance v. Pakistan, Switzerland complained to the ICSID
Secretariat that the tribunal had failed to seek its interpretive views before reaching
a controversial interpretation of the BIT umbrella clause. The Swiss authorities made
clear that they rejected the narrow reading given to the umbrella clause by the tribunal.60
To avoid such complaints, future tribunals may be enticed to involve the contracting
parties in the interpretation process.

V. Conclusion
Both, States and arbitral tribunals have a role to play in the interpretation of IIAs. As
masters of their treaties, States have numerous tools at their disposal to influence
how tribunals interpret IIAs. From drafting clear and precise treaty language, to issuing
joint interpretive notes or making unilateral statements States can guide the process
of interpretation through actions relating to the different stages of an IIA’s lifetime.
Entry points for States’ pro-active engagement for guiding arbitral tribunals in the
interpretation of IIAs can either be derived from public international law, in particular
the VCLT rules on interpretation, or made available through the inclusion of specific
mechanisms in an IIA. In practice, however, interpretative tools have been rarely used
and the principle task of giving meaning to rights and obligation in IIAs has been left to
arbitral tribunals.

In light of the challenges posed by investor-State arbitration, State parties may
benefit from exercising their interpretive powers in a more assertive and proactive
manner. Interpretive instruments often involve little cost and do not require ratification
procedures, yet they can direct tribunals in their reading of IIA obligations. Interpretation
can thus play an important supplementary role in ongoing efforts to reform the current
IIA regime with a view to strengthening its contribution to sustainable development.

In addition, international organizations can also play a role, for example, by providing
analysis of tribunals’ recent treaty interpretations or of the procedures through which
cases have been settled and awards rendered.

60 Société Générale de Surveillance v. Pakistan (Pakistan-Switzerland BIT), Switzerland submitted: "[T]he Swiss authorities
are wondering why the Tribunal has not found it necessary to enquire about their view on the meaning of Article 11 [the
umbrella clause] in spite of the fact that the Tribunal attributed considerable importance to the intent of the Contracting
Parties in drafting this Article and indeed put this question to one of the Contracting Parties (Pakistan). . . . [T]he Swiss
authorities are alarmed about the very narrow interpretation given to the meaning of Article 11 by the Tribunal, which not
only runs counter to the intention of Switzerland when concluding the Treaty but is quite evidently neither supported by the
meaning of similar articles in BITs concluded by other countries nor by academic comments on such provisions. " Note on
the Interpretation of Article 11 of the Bilateral Investment Treaty Between Switzerland and Pakistan, attached to the Letter
of the Swiss Secretariat for Economic Affairs to the ICSID Deputy-Secretary General (1 October 2003), reprinted in Mealey’s
Int’l Arb. Rep., Feb. 2004.


Figure 2. Policy options for States

Interpretive instruments of States

Joint Unilateral

IIA Drafting

• Clear and precise

• Reference to rules of

• Reference to other fields
of international law

• Appropriate objectives in
the preamble

IIA Conclusion
• Formal side-agreements
• Informal side-instruments

• Statements and
documents of the
ratification process

IIA in Force

• Ad-hoc authoritative

• Authoritative
interpretation by treaty

• Release of travaux

• Unilateral documents
and declarations

• Model BITs


• Renvoi-mechanism of
interpretive questions*

• Consultation of draft

• Intervention of non-
disputing State Party*

• Expert advice

Post-Dispute • Public evaluation of rendered awards

* only available if explicitly provided for in the IIA

For the latest investment trends
and policy developments, including

International Investment Agreements (IIAs),
please visit the website of the UNCTAD

Investment and Enterprise Division

For further information,
please contact

Mr. James X. Zhan

Investment and Enterprise Division

Tel.: 00 41 22 917 57 60
Fax: 00 41 22 917 04 98