Introduction

The SWIFT MT199 message is a free-format communication tool used extensively in interbank and corporate-to-bank messaging. Unlike structured SWIFT messages like MT700 or MT760, MT199 allows for flexible content, making it suitable for clarifications, notifications, and ad-hoc instructions.

Understanding its structure and key components ensures proper usage, reduces miscommunication, and maintains the integrity of interbank communication.

Keywords: transaction reference number (Field 20), related reference (Field 21), narrative text (Field 79), SWIFT message format.
Related terms: message header, free text field, non-transactional information.

I. Overview of MT199 Structure

An MT199 message is composed of three main elements that provide context, reference, and communication details:

1. Message Header – identifies the sender, receiver, and message type.

2. Reference Fields – link the MT199 to related transactions for clarity.

3. Narrative Text – contains the free-format content detailing the communication purpose.

This combination allows MT199 to be flexible yet traceable, ensuring that recipients can interpret the message correctly within their operational and compliance frameworks.

II. Key Fields of MT199

1. Field 20 — Transaction Reference Number

• Purpose: Provides a unique reference identifier for the MT199 message.

• Importance: Allows both sender and receiver to track the communication efficiently.

• Format: Typically alphanumeric, defined by the sending bank’s SWIFT system.

Example:

Field 20: TRN1234567890

This reference ensures the MT199 can be linked to internal logs or previous communications.

2. Field 21 — Related Reference

• Purpose: References a prior message or transaction relevant to the current MT199.

• Importance: Establishes a connection to a related financial operation, such as MT700, MT760, or another MT199.

• Format: Usually an alphanumeric code corresponding to the related SWIFT message.

Example:

Field 21: RELMT700987654

This clarifies the context and avoids misinterpretation of the message’s purpose.

3. Field 79 — Narrative Text (Free-Format Field)

• Purpose: Contains the main content of the MT199, written in plain text.

• Importance: Conveys instructions, clarifications, or notifications in a flexible, non-standardized format.

• Best Practice: Keep content concise, clear, and unambiguous to prevent miscommunication. Avoid implying binding obligations.

Example Content:

“This message is provided to confirm receipt of documents and clarify shipment instructions. No financial commitment is implied.”

Field 79 allows banks to communicate non-transactional information securely, making MT199 highly adaptable.

4. Additional Message Elements

• Message Header: Contains sender and receiver BIC codes and SWIFT routing information.

• Trailer Block: Ensures message integrity and authentication within the SWIFT network.

• Optional Fields: Some MT199s may include additional fields for internal bank processing or compliance notes.

III. Best Practices for Using MT199 Components

1. Always reference prior transactions using Field 21 to provide context.

2. Keep Field 79 narrative precise — avoid technical jargon or ambiguous statements.

3. Use proper transaction references in Field 20 to maintain traceability.

4. Verify message header and routing information to prevent delivery errors.

5. Maintain a record of MT199 messages for compliance and audit purposes.

Keywords: SWIFT message format, free text field, non-transactional information.

IV. Common Use Cases

• Clarifying details of a previously issued Letter of Credit (LC) or Standby Letter of Credit (SBLC).

• Communicating updates on fund transfers or procedural matters.

• Notifying banks about document receipt or internal operational status.

• Coordinating interbank actions in ad-hoc or exceptional situations.

V. Limitations of MT199

• MT199 is non-binding and cannot replace formal financial instruments.

• Free-format nature may lead to misinterpretation if narrative is unclear.

• It should not be used to initiate payments or guarantees; structured SWIFT messages remain necessary for formal financial obligations.

VI. Conclusion

The MT199 message is a vital communication tool in international banking, offering flexibility and secure transmission of non-standard or supplementary information.
By understanding the structure and key components — particularly Fields 20, 21, and 79 — institutions can ensure clarity, maintain traceability, and reduce operational risks in interbank messaging.

MT199 acts as a bridge for effective communication, complementing formal SWIFT messages while maintaining a non-binding, informational purpose.

FAQ: Structure and Key Components of MT199

Q1 — What is Field 20 in MT199 used for?
It provides a unique transaction reference number to track the MT199 message.

Q2 — Why is Field 21 important?
Field 21 references a related transaction for clarity and context.

Q3 — What is the role of Field 79?
Field 79 contains the narrative text, conveying instructions, clarifications, or updates.

Q4 — Can MT199 be used for payment instructions?
No. MT199 is non-binding and used only for communication purposes.

Q5 — How do banks maintain compliance using MT199?
By logging all messages, referencing related transactions, and writing clear, unambiguous narratives in Field 79.