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Field 20 on an MT103 is the Sender's Reference — the unique identifier the sending bank assigns to the payment. It is mandatory.
How an MT103 maps to the UETR (field 121), sender reference (field 20), value-date/currency/amount (field 32A) and beneficiary details. Source: SWIFT MT103 specification.
Details
Format: up to 16 characters of letters, digits and slashes. Cannot start or end with a slash, and cannot contain two consecutive slashes.
Often referred to as the TRN (Transaction Reference Number) by customer-service staff.
For end-to-end tracking across multiple banks the UETR in field 121 is more reliable, because field 20 is unique only within the issuing bank.
Quick facts
SWIFT field specification
Example value
:20:REF20251015-001
Valid characters / format
16x alphanumeric, no slashes
Required on MT103
Mandatory
Required on MT202
Mandatory
Required on pacs.008
Optional
Notes
Sender reference (TRN). Carried in <InstrId> on pacs.008.
Key facts
Mandatory MT103 field
Format: 16x — up to 16 letters/digits/slashes
Assigned and unique inside the sending bank only
Used as the customer-facing "reference" or "TRN"
Frequently asked questions
Is field 20 the same as a UETR?
No. Field 20 is bank-specific. The UETR (field 121) is global and travels through every bank in the chain.
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