On 19 June 2023, the Bank of England completed the migration of CHAPS - the UK's high-value payment system - to ISO 20022 messaging. The migration replaced the legacy SWIFT MT message format with the new MX format for all CHAPS payment instructions, making CHAPS one of the first major RTGS systems globally to complete the transition.
Migration Approach
The Bank of England adopted a "like-for-like" migration approach, meaning that the initial ISO 20022 implementation carried the same data content as the legacy MT messages. This minimized the risk of the cutover while establishing the new messaging format on the system.
The migration was implemented as a big-bang cutover over a single weekend. From the Monday following the migration, all CHAPS messages were exclusively in ISO 20022 format. There was no coexistence period for CHAPS itself, though SWIFT's broader cross-border coexistence continued.
Enhanced Data Capabilities
While the initial migration was like-for-like, the move to ISO 20022 opened the door for CHAPS to carry richer data in subsequent phases. Structured addresses, Legal Entity Identifiers (LEIs), enhanced purpose codes, and extended remittance information could all be carried in the MX message format.
The Bank of England published a roadmap for progressively mandating these enhanced data elements, with structured addresses and LEI requirements being phased in over subsequent years.
Significance for the UK Market
The CHAPS migration was a critical milestone for the UK payments industry. As the country's RTGS system processing over GBP 400 billion daily, CHAPS is the backbone of sterling settlement. Its migration to ISO 20022 aligned it with other major systems - including T2 in the eurozone and the planned Fedwire migration in the US - and positioned the UK at the forefront of the global transition to structured payment messaging.
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