SWIFT FIN

SWIFT FIN is the core messaging service of SWIFT, the cooperative that runs the main international network for financial messages. FIN carries structured messages in SWIFT's traditional MT message format between banks, broker-dealers, market infrastructures and corporations, using a store-and-forward model in which SWIFT receives each message, validates it, stores it and delivers it to the recipient. The best-known FIN message is the MT103 single customer credit transfer used for cross-border payments.

FIN should be distinguished from SWIFT's other services. InterAct supports real-time and store-and-forward exchange of XML messages, including ISO 20022 messages often called MX messages, and FileAct is used for bulk file transfer. All of them run over SWIFT's secure IP network. FIN itself does not move money: a FIN message is an instruction, and the actual settlement happens through accounts between banks or in payment systems.

Each institution connects to SWIFT through approved interface software and is identified by its Business Identifier Code (BIC). When a bank sends a FIN message, SWIFT checks that the sender is authorised, that the message follows the syntax rules for its type and that mandatory fields are present. It then acknowledges receipt to the sender, stores the message and delivers it to the receiver when that receiver is connected. If the receiver is offline, the message waits in storage until it reconnects.

This model gives FIN several properties valued by banks: guaranteed delivery, an audit trail of every message, non-repudiation through security controls and acknowledgements, and the ability to query and retrieve past messages. Relationship management controls let institutions restrict which counterparties can send them certain message types.

Messages are built from numbered fields with fixed formats, such as field 32A for the value date, currency and amount of a payment, and field 71A for the charging option. Senders and receivers rely on these conventions, and on usage guidelines agreed by market practice groups, so that automated systems can process messages without manual intervention.

MT messages are grouped into categories by the first digit of their number:

• Category 1. Customer payments and cheques, including the MT103 and the multiple customer transfer MT102.
• Category 2. Financial institution transfers, such as bank-to-bank payments and cover messages.
• Category 3. Treasury markets, including foreign exchange and money market confirmations.
• Category 5. Securities markets, including settlement instructions and confirmations.
• Category 7. Documentary credits and guarantees used in trade finance.
• Category 9. Cash management and customer status, such as statements and confirmations of debit and credit.

Other categories cover collections, precious metals, syndications and system messages.

FIN Copy is a feature that lets a central institution receive a copy of payment messages exchanged between participants, either in full or in part, and, in some configurations, approve the payment before it is delivered. Several real-time gross settlement systems used this design, in which participating banks send payment messages to each other over FIN while the central bank settles each one in its accounts before release. Many of these systems have since moved to ISO 20022 messaging as part of system renewals.

The financial industry has been moving from MT to ISO 20022, which offers richer, more structured data for compliance screening, reconciliation and automation. For cross-border payments and cash reporting, SWIFT ran a coexistence period from March 2023 in which both formats were allowed, and ended it in November 2025 for the main payment instruction messages, after which these are expected to be sent in ISO 20022 form, such as pacs.008 instead of MT103. Translation services help institutions that have not fully converted their internal systems. MT messages in other categories, such as securities and trade finance, continue on FIN while their own migration plans develop.

For decades FIN has been the backbone of correspondent banking and international payments, carrying messages for most of the world's banks. Its reliability and security made it a standard, but its fixed formats and limited fields constrained the data that could travel with a payment, contributing to manual repairs and compliance delays. Tracking improvements through SWIFT gpi and the shift to ISO 20022 have addressed some of these issues. Access to SWIFT messaging has also become a tool of foreign policy, as disconnecting banks from the network has been used as a sanction.