acmt.023 — Identification Modification Advice

The message that propagates the modification of a party or account identifier: name change, address change, IBAN change. Pivot of the ISO 20022 banking identification-vigilance workflow.

Purpose and place in the flow

acmt.023 is an identification modification advice sent to notify that identification details of a party (name, address, legal identifier) or account (number, associated BIC) have changed. It is a building block of the Identification Verification process in the ISO 20022 Account Management workflow.

Typical use cases: a SEPA Direct Debit debtor changes its legal name (merger, acquisition) — the creditor receives an acmt.023 to update its master data before the next SDD. A correspondent bank notifies an account migration (IBAN change due to internal reorganisation). A scheme operator (e.g. Bacs in the UK) broadcasts identifier changes to every participant.

XML structure

The message is wrapped in <Document> with the version namespace, then in the root <IdModAdvc>. Two main blocks:

• Assgnmt (Assignment) — sending metadata: Id unique identifier, Assgnr (assigner — sender), Assgne (assignee — recipient), CreDtTm creation datetime.
• Mod (Modification) — the modification itself, repeatable 1 to n. Each Mod contains two sub-blocks: OrgnlPtyAndAcctId (original state) and UpdtdPtyAndAcctId (updated state). The recipient compares both to detect changed fields.

Key fields

• Assgnmt/Id — unique advice identifier (max 35 chars). Keep for matching a potential acmt.024 response.
• Assgnmt/Assgnr/Agt/FinInstnId/BICFI — sender BIC (the bank detecting / announcing the change).
• Assgnmt/Assgne/Agt/FinInstnId/BICFI — recipient BIC (the bank that must update its master data).
• Mod/OrgnlPtyAndAcctId/Pty/Pty/Nm — party name before modification.
• Mod/OrgnlPtyAndAcctId/Acct/Id/IBAN — IBAN before modification (may be identical to the one in UpdtdPtyAndAcctId if only the party changes).
• Mod/UpdtdPtyAndAcctId/Pty/Pty/Nm — new name.
• Mod/UpdtdPtyAndAcctId/Pty/Pty/PstlAdr — new structured address.
• Mod/UpdtdPtyAndAcctId/Acct/Id/IBAN — new IBAN (may differ in case of BBAN re-codification).

XML example

ACME SARL changes its legal form (becomes ACME SAS) and relocates from the 1^st arrondissement (12 rue de la Soie) to the 3^rd (15 avenue de la Republique). BNP Paribas notifies Deutsche Bank:

<?xml version="1.0" encoding="UTF-8"?>
<Document xmlns="urn:iso:std:iso:20022:tech:xsd:acmt.023.001.04">
  <IdModAdvc>
    <Assgnmt>
      <Id>MOD-2026-05-14-001</Id>
      <Assgnr>
        <Agt>
          <FinInstnId><BICFI>BNPAFRPP</BICFI></FinInstnId>
        </Agt>
      </Assgnr>
      <Assgne>
        <Agt>
          <FinInstnId><BICFI>DEUTDEFF</BICFI></FinInstnId>
        </Agt>
      </Assgne>
      <CreDtTm>2026-05-14T10:00:00+01:00</CreDtTm>
    </Assgnmt>
    <Mod>
      <OrgnlPtyAndAcctId>
        <Pty>
          <Pty>
            <Nm>ACME SARL</Nm>
            <PstlAdr>
              <StrtNm>12 rue de la Soie</StrtNm>
              <TwnNm>Lyon</TwnNm>
              <PstCd>69001</PstCd>
              <Ctry>FR</Ctry>
            </PstlAdr>
          </Pty>
        </Pty>
        <Acct>
          <Id><IBAN>FR7630006000011234567890189</IBAN></Id>
        </Acct>
        <Agt>
          <FinInstnId><BICFI>BNPAFRPP</BICFI></FinInstnId>
        </Agt>
      </OrgnlPtyAndAcctId>
      <UpdtdPtyAndAcctId>
        <Pty>
          <Pty>
            <Nm>ACME SAS</Nm>
            <PstlAdr>
              <StrtNm>15 avenue de la Republique</StrtNm>
              <TwnNm>Lyon</TwnNm>
              <PstCd>69003</PstCd>
              <Ctry>FR</Ctry>
            </PstlAdr>
          </Pty>
        </Pty>
        <Acct>
          <Id><IBAN>FR7630006000011234567890189</IBAN></Id>
        </Acct>
        <Agt>
          <FinInstnId><BICFI>BNPAFRPP</BICFI></FinInstnId>
        </Agt>
      </UpdtdPtyAndAcctId>
    </Mod>
  </IdModAdvc>
</Document>

• Assgnr BNP Paribas → Assgne Deutsche Bank.
• OrgnlPtyAndAcctId carries the original state (ACME SARL, former HQ, unchanged IBAN).
• UpdtdPtyAndAcctId carries the new state (ACME SAS, new HQ, same IBAN).
• The recipient compares the two blocks to identify the changed fields (Name + StrtNm + PstCd).

Versions

Common pitfalls

• No detectable diff between OrgnlPtyAndAcctId and UpdtdPtyAndAcctId — if both blocks are strictly identical, the receiver ignores the message. Ensure at least one field differs.
• Unstructured address — version 001.04 mandates structured sub-elements (StrtNm, BldgNb, PstCd, TwnNm, Ctry). No free AdrLine.
• IBAN change without party change — possible but rare. Ensure that OrgnlPtyAndAcctId/Acct/Id/IBAN indeed differs from UpdtdPtyAndAcctId/Acct/Id/IBAN and that the Pty remains identical. Otherwise it is an account transfer, not a modification.
• No effective-date mechanism — acmt.023 does not carry an effective date (from when the new identification applies). Handle out-of-band or via Mod/ModRsn free text.
• Sender / recipient BICs swapped — Assgnr sends to Assgne. Mixing them causes a logical rejection at the gateway.
• No formal response — many implementations do not send an acmt.024 confirmation. Track sent advice on the sender side and plan periodic reconciliation.

Related messages

• acmt.024 — Identification Verification Report: response to acmt.023 that confirms the final identity.
• acmt.022 — Notification Of Account Closure: closure notification (extreme case of modification).
• acmt.025 — Account Switch Information Response: used in account portability workflows.
• pain.008 — SDD: directly benefits from identification updates.
• pacs.008 — indirectly references the updated Pty.