In 2015, regulations were made that gave effect to the agreements and arrangements reached between the UK and other countries to improve international tax compliance, including the common reporting standard (CRS) developed by the OECD and the US Foreign Account Tax Compliance Act (FATCA). ICAEW has previously published guidance on CRS and FATCA.  

The regulations were amended in July 2025 to align with updates to the CRS. The changes include the introduction of new mandatory registration requirements. 

Registration required 

The following must register with HMRC by 31 December 2025 (or, if later, the 31 January following the calendar year in which they fall within CRS or FATCA rules): 

1. UK reporting financial institutions (RFIs). This is the case regardless of whether the RFI has any financial accounts to report (known as ‘reportable accounts’). Previously, such institutions were not required to register if they had no reportable accounts. There is, however, no requirement to submit a nil annual return where the RFI has no reportable accounts. 
2. UK trustee-documented trusts (TDTs). Broadly, TDTs are trusts that either hold financial assets (such as an investment portfolio) which are professionally managed or have a professional trustee (such as a corporate trustee). The TDT is required to register with HMRC regardless of the residency of the account holders (which could be the settlor, trustees, protector or beneficiary, depending on the structure).  

How to register 

Registration is through HMRC’s AEOI portal, which is a one-off requirement. For TDTs, the information that must be provided is similar to that supplied under the trust registration service (TRS). Registration must be in the trust’s name and not that of the trustees, with the reporting trustee shown as a contact. 

Penalties 

HMRC can charge a penalty of £1,000 for failing to register on time, with further penalties of £300 per day if the failure continues after the initial penalty notice has been issued. 

Other changes 

Most charities will now be excluded from the CRS and can deregister for CRS from 1 January 2026. 

From 1 January 2026, CRS will expand to cover the reporting of cryptoasset transactions (known as the cryptoasset reporting framework (CARF)). 

Further information 

• IEIM404510 - Mandatory Registration - HMRC internal manual - GOV.UK 
• What’s CARF got to do with it? | ICAEW