sese.028 — Securities Settlement Conditions Modification Status Advice

The status of a post-instruction modification request. When a custodian tries to amend an already-issued sese.023 instruction — changing the date, account, price — the CSD replies with this message: accepted, rejected, pending.

Purpose and place in the flow

sese.028 replies to a post-instruction modification request. The custodian has issued a sese.030 asking to amend an acknowledged sese.023; the CSD replies via sese.028 with one of:

• ACPT — Accepted, the modification is applied.
• REJT — Rejected, refused modification with reason (often MEND = modification too late).
• PEND — Pending, awaiting verification or counterparty matching.
• PACK — Partial Acknowledgment, some fields modified, others not.

The timing is critical: modifications on matched instructions (with counterparty) have a narrow window, typically < 60 minutes before the settlement target. Once matching is done, modifications require a new instruction and the cancellation of the old via sese.020.

XML structure

• ModReqRef — Modification Request Reference: original sese.030 reference.
• TxIdDtls — Transaction ID Details: TxId on the account-owner side and account-servicer side (matching reference).
• PrcgSts — Processing Status: status + reason.
• AcctOwnr — Account Owner: BIC of the custodian that requested the modification.
• SfkpgAcct — Safekeeping Account: account concerned.

Key fields

• ModReqRef/Ref — original sese.030 reference.
• TxIdDtls/AcctOwnrTxId — transaction identifier on the custodian side.
• TxIdDtls/AcctSvcrTxId — transaction identifier on the CSD side (assigned at sese.023).
• PrcgSts/Sts/Cd — status (ACPT, REJT, PEND, PACK).
• PrcgSts/Rsn/Cd — reason code: MEND (modification too late), CUST (custody refused), INVA (invalid modification field)…
• PrcgSts/Rsn/AddtlRsnInf — narrative mandatory on REJT to enable resolution.

XML example

DTCC refuses a modification request from BNP Paribas: the sese.023 instruction has already been matched with Goldman Sachs Custody, and settlement is due within an hour. Modification rejected for MEND reason:

<?xml version="1.0" encoding="UTF-8"?>
<Document xmlns="urn:iso:std:iso:20022:tech:xsd:sese.028.001.09">
  <SctiesSttlmCondsModStsAdvc>
    <ModReqRef>
      <Ref>BNPP-MOD-20260516-001</Ref>
    </ModReqRef>
    <TxIdDtls>
      <AcctOwnrTxId>BNPP-SETT-20260514-001</AcctOwnrTxId>
      <AcctSvcrTxId>DTCC-7894561230</AcctSvcrTxId>
    </TxIdDtls>
    <PrcgSts>
      <Sts>
        <Cd>REJT</Cd>
      </Sts>
      <Rsn>
        <Cd>MEND</Cd>
        <AddtlRsnInf>MODIFICATION TOO LATE — TRADE ALREADY MATCHED AND PENDING SETTLEMENT WITHIN 1 HOUR WINDOW</AddtlRsnInf>
      </Rsn>
    </PrcgSts>
    <AcctOwnr>
      <Id>
        <AnyBIC>
          <AnyBIC>BNPAFRPP</AnyBIC>
        </AnyBIC>
      </Id>
    </AcctOwnr>
    <SfkpgAcct>
      <Id>BNPPSAFEKEEP-NYSE-001</Id>
    </SfkpgAcct>
  </SctiesSttlmCondsModStsAdvc>
</Document>

Consequence for BNP: must either accept the settlement as is, or quickly issue a sese.020 (cancellation request) before the settlement target — but with high risk that the CSD also refuses the cancellation that late.

Common pitfalls

• Missing ModReqRef — without the original sese.030 reference, the custodian cannot reconcile; ETL stuck.
• REJT without Rsn — a REJT without reason exposes to unnecessary operational escalations. Always document the reason via Cd + AddtlRsnInf.
• AcctOwnrTxId / AcctSvcrTxId confusion — both references must be present for bilateral matching. Mixing one for the other breaks reconciliation.
• Prolonged PEND — a PEND status must be followed by ACPT or REJT within the agreed SLA (typically minutes). Beyond, explicit follow-up.
• Multi-field partial modification — on PACK, only some fields are modified. Always explicitly list which fields were accepted vs refused via narrative.

Related messages

• sese.023 — Securities Settlement Transaction Instruction, the original instruction.
• sese.024 — Securities Settlement Status Advice (general instruction status).
• sese.030 — Securities Settlement Conditions Modification Request (the request that triggers sese.028).
• sese.031 — Settlement Conditions Modification.