Troubleshooting MT and ISO 20022 Messages
The questions settlement, custody, payments and reconciliation teams ask when a message is rejected, an instruction does not match or a statement does not add up. Each page explains what is happening, the usual causes, the steps to fix it and an example you can open in the parser.
Securities settlement
Unmatched, pending, failing and rejected settlement instructions.
- Why is my settlement instruction unmatched (NMAT)?
Why a settlement instruction stays unmatched (MT548 NMAT), which matching fields the CSD compares, the T2S amount tolerance and how to fix each reason code.
- MT548 PEND LACK: pending for lack of securities
What MT548 25D::SETT//PEND with reason LACK means, how it differs from CLAC, when it turns into PENF and the steps to get the delivery settled.
- MT548 PENF: why is my settlement failing?
What MT548 25D::SETT//PENF means, the common failing reasons, how EU CSDR cash penalties apply since 1 February 2022 and the steps to get a fail settled.
- MT548 rejected instruction (IPRC//REJT): reasons and how to re-instruct
Why an account servicer rejects a settlement instruction (MT548 IPRC//REJT), what each reason code such as SAFE, DDAT or DSEC means and how to re-instruct.
- MT535 positions do not match my books: how to reconcile
Why MT535 holdings differ from your books: settled vs traded basis, pending trades, corporate actions, blocked balances, cut-offs, and using MT536 and MT537.
Corporate actions and custody
Notifications, instructions and custody statements that do not add up.
- MT564 vs MT568: which one carries the corporate action details?
MT564 or MT568: which one carries the corporate action details, when narrative comes in an MT568, how they link by CORP reference and how to process both.
- MT567: why was my corporate action instruction rejected?
What an MT567 with 25D::IPRC//REJT means for your MT565 election, what reasons such as LACK, OPNM or LATE mean, and how to re-instruct before the deadline.
Payments
Rejected payments, references and the move to ISO 20022.
- Why was my MT103 rejected with a NAK error code?
Why Swift NAKs an MT103: how network validation works, what T, C, D and E error codes mean, a table of common codes with fixes, and the 2025 contingency checks.
- What do pacs.002 status and reject reason codes mean?
pacs.002 status and reason codes explained: TxSts values such as ACSC, ACCC, PDNG and RJCT, common StsRsnInf codes with fixes, and when a pacs.004 return follows.
- Why is data truncated when an ISO 20022 payment is translated to MT?
Why data is cut when a pacs.008 is translated to MT103 (and the reverse): names, structured addresses, LEIs, remittance, purpose codes, the + marker and what to do.
- How do I read field 32A (value date, currency, amount)?
Field 32A decoded: the YYMMDD date, ISO currency, comma decimal and the 15d length rule, decimals per currency, common rejects and the pacs.008 equivalent.
Statements
Bank statements that do not balance or are hard to read.
- Why does my MT940 opening balance plus entries not equal the closing balance?
Why an MT940 does not add up: missing pages in 28C, 60M and 62M intermediate balances, RC and RD reversals, duplicates and value dates, with a worked example.
- How do I read field 61 in an MT940 statement?
Field 61 of the MT940 decoded: value and entry date, D/C mark including RC and RD, funds code, amount, S, N and F transaction types, references and NONREF.
- What is the difference between camt.053 and MT940?
camt.053 compared with MT940: balances, entries, EndToEndId and UETR references, bank transaction codes, batch bookings, and what a conversion to MT940 drops.
Identifiers and fields
IBANs, BICs, UETRs and the fields people misread most.
- How do I read a UETR and use it to track a payment?
What a UETR is, how its 36 characters are built, where it sits in MT (field 121) and MX (PmtId/UETR), the pass-on rules and the mistakes that break tracking.
- Why was my payment rejected or returned for a wrong IBAN or BIC?
How IBAN check digits work (mod 97, with a worked example), IBAN lengths by country, how a BIC is built, test BICs, and the return codes AC01, AC04, BE01, RC01.