HMRC to End Combined AEOI Schema: What Financial Institutions Need to Know

What is changing in HMRC’s AEOI reporting requirements?

HMRC has confirmed that from 1 January 2027, financial institutions in the UK will no longer be able to submit their Automatic Exchange of Information (AEOI) returns using the current combined schema for the Common Reporting Standard (CRS) and the Foreign Account Tax Compliance Act (FATCA).

Instead, firms will need to submit CRS and FATCA reports using two separate XML schemas:

• The amended CRS XML schema published by the OECD in October 2024.
• The IRS FATCA XML schema (Form 8966), published in January 2017.

This marks the end of the combined UK schema and signals a move to globally standardised approaches maintained directly by the OECD and IRS.

When does the change take effect?

The combined CRS/FATCA schema will remain valid until 31 December 2026. From 1 January 2027, only the OECD’s amended CRS schema and the IRS FATCA schema will be accepted.

Importantly, HMRC has clarified that all XML submissions after this date, including those relating to previous calendar years, must use the new schemas. This means that firms correcting or resubmitting past years’ reports after 2027 cannot rely on the old combined schema.

Why is HMRC discontinuing the combined CRS/FATCA schema?

The decision reflects a global move towards greater standardisation and alignment:

• The OECD updated its CRS XML schema in October 2024, reflecting refinements and amendments agreed by participating jurisdictions.
• The IRS has consistently required FATCA submissions to follow its 2017 schema for Form 8966, which includes detailed business rules and validation requirements.

By discontinuing its bespoke combined schema, HMRC is bringing UK reporting in line with international standards. This is expected to simplify cross-border compliance for multinational financial institutions, though it creates a short-term transition challenge for firms currently relying on the UK-specific combined format.

How will CRS and FATCA reports be submitted to HMRC after 2027?

The UK Government Gateway portal will remain the submission channel. Financial institutions will need to:

• Prepare separate CRS and FATCA XML reports using the OECD and IRS schemas.
• Upload these reports via the Reportable Account submission schema on the HMRC portal.

For institutions with very few reportable accounts, HMRC will continue to provide a form-based system allowing manual entry of account data. However, most financial institutions will require automated XML submissions due to reporting scale and complexity.

What are the main differences between the current UK combined schema and the new CRS and FATCA schemas?

The transition is more than cosmetic. Key changes include:

• Separation of schemas: Firms must now create and maintain distinct processes for CRS and FATCA submissions.
• Updated CRS rules: The OECD’s 2024 amended schema introduces technical changes and updated business rules that must be applied to all CRS filings.
• FATCA alignment: Firms will need to adhere to the IRS’s long-standing FATCA schema, which has detailed validations that differ from the CRS structure.
• Back-reporting requirement: Even historical years submitted after 2026 must comply with the new schemas.

This means financial institutions cannot rely on mapping tools designed for HMRC’s combined schema and will need schema-specific compliance solutions going forward.

What challenges will financial institutions face in making the transition?

The most significant challenges include:

• Dual data preparation: Firms must separate CRS and FATCA reporting data, ensuring each dataset aligns with the correct schema.
• System upgrades: Legacy reporting systems built around the combined schema may not be compatible with the new OECD and IRS schemas.
• Operational risk: Without robust systems in place, firms face a higher risk of rejected filings, delays, and potential compliance penalties.

How can XML Authority help with CRS and FATCA reporting after 2027?

The upcoming changes reinforce the need for a flexible XML reporting solution that can handle both schemas without unnecessary complexity.

XML Authority is already equipped to support both the amended OECD CRS schema (2024 version) and the IRS FATCA schema (2017 version).

With XML Authority, financial institutions can:

• Maintain separate datasets for CRS and FATCA, ensuring that each submission is correctly structured for its schema.
• Use our report setup wizard to create simplified schema structures tailored to your needs (for example, focusing only on individual account holders). This reduces complexity by stripping away fields that don’t apply to your business model.
• Validate at the schema level, so you can be confident that each file is technically correct before submission to HMRC.
• Prepare historical and future filings in line with the new requirements, including corrections for prior years after 2027.

By combining schema accuracy with a user-friendly setup wizard, XML Authority makes what could be a complex transition into a straightforward, manageable process.

What steps should firms take now to prepare for the 2027 deadline?

The discontinuation of HMRC’s combined CRS/FATCA schema is a significant shift, and while the deadline may feel distant, firms that act early will avoid the last-minute scramble. From 2027 onwards, all CRS and FATCA submissions — including corrections for past years — must be created on two separate XML schemas.

The best way to prepare is to start working with the amended OECD CRS schema and the IRS FATCA schema now.

XML Authority makes this transition simple. With our solution, you can:

• Set up and validate CRS and FATCA datasets separately, ensuring compliance with each schema.
• Use our report setup wizard to quickly generate simplified schema structures tailored to your institution (for example, individual-only account holders), removing unnecessary complexity.
• Upload directly to HMRC in the correct formats with confidence that your files meet schema-level validations.

Try XML Authority Free for Two Months

We’re offering a free 2-month trial of XML Authority, giving you the opportunity to prepare your datasets, familiarise your teams with the new schemas, and validate reports ahead of the 2027 deadline.

By starting now, you can build confidence in your reporting process, reduce compliance risk, and ensure your transition is smooth when the combined schema is retired.