ISO 6166:2021

INTERNATIONAL ISO
STANDARD 6166
Redline version
compares Eighth edition to
Seventh edition
Financial services — International
securities identification number (ISIN)
Reference number
ISO 6166:redline:2021(E)
©
ISO 2021
ISO 6166:redline:2021(E)
IMPORTANT
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This marked-up version highlights the main changes in this edition of the document
compared with the previous edition. It does not focus on details (e.g. changes in
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ii © ISO 2021 – All rights reserved

ISO 6166:redline:2021(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principles . 2
4.1 Constituents. 2
4.2 Financial instruments Instruments for which the ISIN is allocated . 3
4.3 Assignment of related codes . 3
5 Registration Authority (RA) . 3
5.1 Name and contact details of the RA Registration Authority . 3
5.2 Service provision . 4
6 ISIN allocation . 4
6.1 General . 4
6.2 Descriptive elements . 4
6.2 6.3 Existing ISINs and existing securities instruments without ISINs . 4
Annex A (normative) ISIN allocation Allocation of prefixes. 5
Annex B (normative) Minimum descriptive elements for each category/  or issue type .9
Annex C (normative) Formula for computing the modulus 10 “double-add-double” check digit .12
Annex D (normative) Basic information and minimum descriptive data
elements Information requirements for ISIN allocation .14
Annex E (informative) Examples.15
Bibliography .18
ISO 6166:redline:2021(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. 2 (see www .iso .org/ directiveswww .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
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iso/ foreword .html.
The committee responsible for this document isThis document was prepared by Technical Committee
ISO/TC 68, Financial services, Subcommittee SC 48, Securities and related financial instrumentsReference
data for financial services.
This seventheighth edition cancels and replaces the sixthseventh edition (ISO 6166:2001ISO 6166:2013),
which has been extended to cover necessary technical changes, the Registration Authority function as
well as the usage of the ISIN recordtechnically revised.
The main changes to the previous edition are as follows:
— clarification that the scope covers financial instruments as well as referential instruments;
— addition of new instrument types to which the ISIN code can be allocated (derivative products with
EZ and ZZ prefix, baskets, emission allowances and carbon credits);
— addition of new minimum descriptive elements (Annex B).
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved

ISO 6166:redline:2021(E)
Introduction
With the rapid expansion of the international securities business, there isinternational business
in financial instruments, there was a need for a universally applicable international securities
identification number (ISIN).
No worldwide numbering system existed at the time of the publication of the first edition of this
International Standarddocument. Countries with a developed securities businessfinancial market
identified issues of securities by means of code numbers, which are without any significance outside the
country concerned. SecuritiesInstruments of the same issue arewere identified by means of different
numbers in the country where they arewere physically held and/or booked. As a result,, booked or both,
with the result that the national numbers may not be applicable in cross-border transactions.
Because of its strong rationalization effect, an internationally applicable numbering system substantially
facilitates and supports international securities businessbusiness in financial instruments. Such a
system is provided by this International Standarddocument. Since the publication of the first edition
of this International Standard, thedocument, its scope has expanded from a focus on securities to a
much broader range of financial instruments. In addition, since the publication of the first edition,
the Registration Authority (RA) relieshas relied on the work of national numbering agencies (NNAs)
which play an integral role in this rationalization effort and in the implementation of this International
Standarddocument.
In preparing this International Standarddocument, care has been taken to conserve the national
systems to the maximum possible extent, not only because of the good routine and valuable experience
collected in this field but also to facilitate the adoption of the worldwide system. Moreover, it is aimed
at creatingprovides a system which is easy to apply internationally and at establishingestablishes
an information network which ensures that the required information can be obtained worldwide
immediately.
INTERNATIONAL STANDARD ISO 6166:redline:2021(E)
Financial services — International securities identification
number (ISIN)
1 Scope
This International Standarddocument provides a uniform structure for the identification of fungible
and non-fungible securities and financialfinancial instruments as well as referential instruments (see
Annex A) using a unique identification numbercode and associated minimum descriptive data (see
Annex B).
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3166 (all parts), Codes for the representation of names of countries and their subdivisions
ISO 4217, Codes for the representation of currencies and funds
ISO 8601 (all parts), Date and time format
ISO 10962, Securities and related financial instruments — Classification of financial instruments (CFI) code)
ISO 17442 (all parts), Financial services — Legal entity identifier (LEI)
ISO 18774, Securities and related financial instruments — Financial Instrument Short Name (FISN)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
fungible
equivalent, substitutable, interchangeable, and not individualized
Note 1 to entry: A fungible financial instrument ranks pari passu in all respects with a different version of the
same financial instrument and can be exchanged into the other version and vice versa at any time.
3.2 3.1
ISIN
international securities identification number
ISIN
alphanumeric code which uniquely identifies a specific security or other financial financial or referential
instrument
ISO 6166:redline:2021(E)
3.3 3.2
ISIN record
record which uniquely identifies a specific security or other financial financial or referential instrument
and consists of the ISIN and the minimum descriptive data elements
Note 1 to entry: For the minimum descriptive data elements, see Annex B.
3.4 3.3
ISIN guidelines
internal  document developed and maintained by the Registration Authority to promote a uniform
process for allocation, registration and dissemination of the ISIN to the financial markets industry
3.4
issuer
legal entity in which the instrument creates an interest
Note 1 to entry: See Annex A.
3.5
issuer
borrower
Note 1 to entry: In the case of debt instruments issued or created by an international branch of a legal entity, the
branch is to be considered as the issuer, not the parent entity.
Note 2 to entry: See Annex A.
3.6
issuer
legal entity that creates or administers the instrument
Note 1 to entry: In the case of shares or units in collective investment vehicles such as investment funds, mutual
funds or hedge funds, the fund is to be considered as the issuer, not the fund management company. H
...