HMRC internal manual

International Exchange of Information Manual

Reportable Information: Tax Identification Number

Reportable Information: Tax Identification Number

The taxpayer identification number (TIN) is the unique identifier assigned to the Account Holder by the tax administration in the Account Holder’s jurisdiction of tax residence. It is a unique combination of letters and/or numbers used to identify an individual or entity for the purposes of administering the tax laws of that jurisdiction.

Any identifier assigned by a jurisdiction of source, for example, for identifying a person whose income has been subject to withholding tax at source, should not be reported.

Some jurisdictions do not issue a TIN and where that is the case there will be nothing to report unless they use other high integrity numbers with an equivalent level of identification. For individuals these include:

  • Social security number
  • National insurance number
  • Citizen or personal identification code or number
  • Resident registration number


For entities, jurisdictions may use a business/company registration code or number where no TIN has been issued.

Some jurisdictions that issue TINs have domestic law that does not require the collection of the TIN for domestic reporting purposes, Australia for example. In such cases the Reporting Financial Institution is not required to collect the TIN for those jurisdictions.

There are also limited circumstances in which residents of some jurisdictions that do issue TINs may nevertheless not have a TIN, for example individuals who have never worked in the jurisdiction and have never been provided with a TIN, and individuals who have moved to the jurisdiction and may not receive a TIN for several years after moving.

Information on the structure and form of TINs used by tax administrations, including those where domestic collection of the TIN is not required, has been published on the OECD website.

The TIN, or TIN equivalent, must be reported for all new accounts [see IEIM403140] where issued.

For pre-existing accounts [see IEIM402640] the TIN is reportable to the extent that it is already held in records maintained by the Reporting Financial Institution [see IEIM402300] or the Reporting Financial Institution is otherwise obliged to collect it.

For the CRS and DAC, where the TIN is not held in respect of pre-existing accounts the Reporting Financial Institution must use reasonable efforts to obtain it [see IEIM402320] by the end of the second calendar year following the year in which the accounts are identified as Reportable Accounts [see IEIM401520]. Not all jurisdictions issue a TIN, or functional equivalent, to all individuals or entities; where a TIN has not been issued to an individual or entity there is an exception from the requirement to report a TIN.  If and when a jurisdiction starts issuing TINs the exception no longer applies and the TIN would be required to be reported if the Financial Institution obtains a self-certification that contains such a TIN, or otherwise obtains such a TIN.

As Reportable Persons may be resident in more than one jurisdiction they may have two or more TINs that the Financial Institution must report.


The TIN to be reported for FATCA purposes is the US Federal Taxpayer Identification Number.

The TIN is a mandatory item for reporting for FATCA in respect of pre-existing accounts for the 2017 reporting year onwards.  However in September 2017 the U.S. Internal Revenue Service published Notice 2017-46 relaxing this requirement

The Notice confirms that foreign financial institutions (FFIs) in Model 1 IGA jurisdictions (including the UK) will not be in significant non-compliance with an applicable IGA during 2017, 2018, and 2019 solely as a result of a failure to report U.S. TINs for preexisting accounts, provided the FFI reports the account holder’s date of birth, makes annual requests for the TIN, and searches its electronic records for missing U.S. TINs before reporting information on 2017.

In view of the IRS Notice and the fact that UK Financial Institutions may find it difficult to obtain TINs for all U.S. account holders, HMRC will not regard a failure by a UK Financial Institution to provide U.S. TINs in respect of preexisting accounts during 2017, 2018 and 2019 as a failure to comply with the UK regulations provided that the requirements of the IRS Notice are met.

In October 2019 the IRS published FAQ3 on Reporting, giving further guidance on reporting TINS for 2020 and future reportable periods:

For reporting in respect of the calendar year 2020 and future years, it will still be possible to report an account without a TIN to HMRC by entering nine zeros in the TIN field.

The IRS FAQ confirms that Financial Institutions are not required automatically to close accounts that do not contain a TIN. 

The IRS FAQ also confirms that if a Financial Institution is unable to obtain a TIN, this will not automatically lead the IRS to conclude that there is significant non-compliance.  Instead, the IRS will consult with HMRC so they can take account of valid reasons why TINs could not be obtained and the efforts made to collect them.  To help with this HMRC will approach Financial Institutions on a case by case basis to gather those reasons and to evidence that the Financial Institution has adequate procedures in place to obtain TINs.

HMRC and the IRS will continue to routinely discuss related matters such as the reasons why TINs cannot be obtained in some circumstances and the evidence of adequate procedures Financial Institutions need to have in place.

Crown Dependencies and Overseas Territories Agreements

For Gibraltar the identifier to be reported for individuals is a social security number.

For Guernsey the identifier to be reported for individuals is a social security number.

For the Isle of Man the identifier to be reported for individuals is a national insurance number.

For Jersey the identifier to be reported for individuals is a social security number.

United Kingdom

For most individuals in the UK the TIN will be their National Insurance Number.