Step 2: Proxy Resolution Messaging Sequence

Following on from Step 1, assuming the Sender entered a proxy, the Source PSP will send Nexus an ISO 20022 acmt.023 message that includes the proxy details.

Proxy resolution flow diagram

1. Nexus (Message Transformation)

Nexus will:

• look for the Country Code in the Assignee > Agent > PostalAddress > Country element

• identify the relevant proxy directory in that country, and

• update the Assignee to the BIC of the proxy directory (or its parent IPS Operator). This is the only change that is made to the message.

2. Nexus -> Destination Proxy Directory

Nexus will send the proxy resolution request to the Destination IPS, who will forward it to the Destination Proxy Directory.

The message will be formatted as an ISO 20022 acmt.023 message. The PDO must be able to accept the message in this format. If the domestic proxy resolution message format is different, the IPSO is responsible for translating the message from the Nexus acmt.023 to the domestic format message before processing the proxy resolution request (See Messaging & Translation for further details.)

Scenario 1: No associated proxy

The Destination Proxy Directory should first check if the proxy is associated with an account.

If there is no associated account, the proxy directory should respond with an acmt.024 response including the appropriate error code in the Report > Verification > Reason > Code element. (See Error codes for further information.)

Scenario 2: Proxy successfully resolved

If the proxy successfully maps to an account, the proxy directory should prepare and return an acmt.024 response message that contains, at a minimum:

• Account details, in the form of either:

  • an IBAN, OR

  • the Financial Institution Identification (eg BIC) AND the Account Identification of the linked account

• the real name associated with the account (wherever possible) – this will be used by the Source PSP when sanctions screening the Recipient.

  • This should be stored in the element UpdatedPartyAndAccountIdentification > Party > Name.

  • Note that wherever possible, the full real name should be returned, as this information supports accurate and automated sanctions screening.

• a display name that can be shown to the Sender to allow them to confirm that the account holder is the intended Recipient. This could be the full name (where privacy and data protection rules allow this to be shown to the Sender) or a partially obscured name, depending on the proxy service.

  • This value should be in the element UpdatedPartyAndAccountIdentification > Account > Name

Note: this is a non-standard use of the Account > Name element, which should normally describe the name of the account rather than the name of the account holder. Unfortunately, the acmt.024 message structure does not currently have a dedicated element for a display name that can be shown to the Sender but which may be different from the real account holder name.

The proxy directory should send this response back to the Nexus.

See Step 3 below for details on how Nexus will handle this response.