ISO 24366:2021

INTERNATIONAL ISO
STANDARD 24366
First edition
Financial services – Natural person
identifier (NPI)
PROOF/ÉPREUVE
Reference number
ISO 24366:2021(E)
©
ISO 2021

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ISO 24366:2021(E)

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© ISO 2021
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Published in Switzerland
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ISO 24366:2021(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Structure of the natural person identifier . 1
5 Check digits . 2
5.1 General . 2
5.2 Calculating the check digits . . 2
6 Natural person identifier data record . 2
Annex A (informative) NPI check digit validation example . 7
Annex B (informative) Conceptual diagrammatic expression . 9
Annex C (informative) Type of name .12
Bibliography .13
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ISO 24366:2021(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 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
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For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 68, Financial services, Subcommittee SC
8, Reference data for financial services.
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.
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ISO 24366:2021(E)

Introduction
Identification of natural persons for the purposes of provision of financial services has specific
applications for protecting the personal data of the employees of financial services firms, allowing
these firms to respond to the requirements of regulation without exposing personal information and
giving regulators a privacy-protected way to identify beneficial owners, among other use cases.
Benefits include straight-through processing savings, the ability to monitor systemic risk across
jurisdictions and, more importantly, the ability to protect citizens' personal information during the
provision of services while responding to regulatory requirements.
This document fulfils the needs of the global financial services industry and the regulatory community
for natural person identification. Its key provisions are that it:
— enables unique identification globally of natural persons requiring an identifier;
— defines a natural person identifier (NPI) code that contains no embedded intelligence;
— defines an NPI code that is interoperable with other standards and existing reference data and can
be applied globally to support the financial services industry;
— leverages the expertise of ISO/TC 68 in defining and maintaining identifier standards;
— defines an NPI scheme that is reliable and an NPI code that is persistent;
— defines an NPI scheme that is extensible and free from limitation on use and redistribution.
Already existing national NPIs might not be applicable in cross-border transactions. The NPI defined
in this document intends to close this gap, allowing a co-existence of national identifiers and the
international NPI.
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INTERNATIONAL STANDARD ISO 24366:2021(E)
Financial services – Natural person identifier (NPI)
1 Scope
This document specifies a machine-readable, unambiguous natural person identifier (NPI) and the
relevant reference data to uniquely identify the natural person relevant to any financial transaction
rather than the personal identifying information.
2 Normative references
The following documents 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 3166-1, Codes for the representation of names of countries and their subdivisions — Part 1: Country
code
ISO/IEC 7064, Information technology — Security techniques — Check character systems
ISO 8601-1, Date and time — Representations for information interchange — Part 1: Basic rules
ISO 17442 (all parts), Financial services — Legal entity identifier (LEI) — Part 1: Assignment
ICAO 9303, Machine Readable Travel Documents
3 Terms and definitions
No terms and definitions are listed in this document.
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/
4 Structure of the natural person identifier
This document uses the following conventions for data element representations:
a) Character representations:
— n: digits (numeric characters 0 to 9 only);
— c: upper-case alphanumeric characters (A to Z and 0 to 9 only).
b) Length indications:
— nn!: fixed length;
— nn: maximum length.
The format of the NPI shall be
— 13!c2!n.
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ISO 24366:2021(E)

The NPI consists of 15 characters decomposed as follows:
— characters (13!c) without separators or “special” characters;
— the 14th and 15th characters (2!n) shall be the check digit pair, as calculated based on the procedure
defined in this document.
5 Check digits
5.1 General
The check digits shall be calculated based on the simplified procedure defined in ISO/IEC 7064 (refer
to MOD 97-10 for the simplified check digit calculation) after the conversion of the (leftmost) 13
alphanumeric characters into a character string consisting only of digits. The check digits are used to
verify the NPI.
Valid check digit pairs are in the range of [02 . 98]. 00, 01 and 99 are not valid NPI check digit pairs.
If the check digits have been calculated correctly, when the entire 15-character NPI is converted to
numbers following the process described in step 1 of 5.2 and divided by 97 as described in step 3 of 5.2,
the remainder shall be “1”.
5.2 Calculating the check digits
Step 1: Any letters in the 13-character string shall be converted to digit pairs in accordance with
ISO/IEC 7064 (MOD 97-10).
A = 10 F = 15 K = 20 P = 25 U = 30
B = 11 G = 16 L = 21 Q = 26 V = 31
C = 12 H = 17 M = 22 R = 27 W = 32
D = 13 I = 18 N = 23 S = 28 X = 33
E = 14 J = 19 O = 24 T = 29 Y = 34
   Z = 35
Step 2: Two zeros shall be appended to the resulting string at the rightmost positions.
Step 3: A Euclidian division of the resulting number by 97 shall be performed to determine the
remainder.
Step 4: The remainder shall be subtracted from 98 to determine the check digit pair.
Step 5: The check digit pair shall be appended to the original 13-character string to arrive at the NPI.
See Annex A for examples
6 Natural person identifier data record
The NPI data record shall be composed of the data attributes shown in Table 1.
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ISO 24366:2021(E)

Table 1 — NPI attributes
Reference data Description M/MwE/O/C Cardi- Discussion/commentary
c
element nality
Legal name – sur- The surname shall be as M 1.1 Where only one name is held by the
name/family/last validated by a valid certif- natural person, that name should
a
name/sole name icate (e.g. birth certificate, be recorded in this field as is usual
passport). policy for jurisdictions where this
convention currently applies.
Where more than one legal name
is held by the natural person, those
names will be captured in the alter-
native name element.
This field shall accommodate alter-
native alphabets and transliteration.
Legal name – The middle name shall be O 0.* This field shall accommodate alter-
a
middle name as validated by a valid cer- native alphabets and transliteration.
tificate (e.g. birth certifi-
Captured: number of middle names
cate, passport).
(check with passport restrictions).
Legal name – The first name shall be as MwE 1.1 Where only one name is held by the
given name/first validated by a valid certif- natural person, that name should
a
name icate (e.g. birth certificate, be recorded in the surname/last
passport). name element as is usual policy for
jurisdictions where this convention
is currently recorded.
This field shall accommodate alter-
native alphabets and transliteration.
Some jurisdictions utilize this field
for first and middle names in official
documentation.
In order to accommodate variations
on how names are structured, the
syntax restrictions on this data
should be xsd: string.
In the case of changing names, the
identifier should stay the same.
Alternative Nicknames, aliases, O 0.* Freeform, unbounded, transliterate.
name(s) “known as”, maiden names,
alterna
...