Guidelines for External Reviews
External Review Service Mapping
Guidelines for External Reviews

These Guidelines for External Reviewers provide voluntary guidance relating to professional and ethical standards for external reviewers, as well as to the organisation, content and disclosure for their reports. They have been developed as a common undertaking between the Executive Committee of the Principles and the Advisory Council in consultation with a group of leading external reviewers, with the support of the ICMA Secretariat with the common objective to promote best practice in the provision of external review services for green, social, sustainability and sustainability-linked bonds.

The guidelines complement the Green and Social Bond Principles, the Sustainability Bond Guidelines, and the Sustainability-Linked Bond Principles and reference other existing relevant guidance such as the Assurance Framework for the Climate Bond Standard, Guidelines for the Conduct Assessment and Certification of Green Bonds (Interim) jointly issued by the People's Bank of China and the China Securities Regulatory Commission, the draft EU Green Bond Standards published by the High-Level Expert Group (HLEG) on Sustainable Finance, and the ASEAN Green Bond Standards.

The 2022 version provides additional guidance especially for Second Party Opinions or verification which are considering climate transition in connection with any Use of Proceeds or Sustainability-Linked Bond issuance, in accordance with the four key elements of the Climate Transition Finance Handbook.


The external reviewers listed below have contributed to, and confirmed that they will voluntarily align with the Guidelines consistent with any regulatory obligations*:


*Please note that ICMA has not investigated or confirmed compliance by the external reviewers with the Guidelines, nor does it recommend, endorse or make any representations regarding the external reviewers listed above.



Translations of the Guidelines for External Reviewers


Please note that the following translations are related to the 2018 edition. They will be updated with the 2021 changes progressively, therefore the edition that each translation currently refers to is indicated below.

External Review Service Mapping

Overview of the External Review Service Mapping

The purpose of the mapping of external reviews is to provide market participants with clear information on the range of services offered as well as the context and content of the final external review report. The Overview is supplied by the templates that external reviewers have provided (see below).

This Excel spreadsheet is divided into 3 tabs: (1) External review services – (2) Timing and coverage – (3) Geographic scope and languages.

To have access to an individual template, you can click on the name of the related provider (on the 1st tab of the Overview).

Download Overview of the External Review Service Mapping

The Overview currently provides information on the following reviewers:


Template for External Reviews

The External Review Service Mapping Template is an excel form where external reviewers are invited to voluntarily provide information about the different external review services they provide.

The Executive Committee of the GBP/SBP encourages external reviewers to voluntarily fill in this template in order to promote transparency and disclosure and support market efficiency.

The accompanying User Guide clarifies how each element of the template should be filled out by external reviewers and interpreted by market participants.

Questions related to the template may be addressed to the Secretariat for the GBP/SBP at greenbonds@icmagroup.org.



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