Anatomy of an MT103: Reading a SWIFT Wire Field by Field
In the last post we compared wires, ACH, and ISO 20022 using everyday examples. Now let's zoom into the actual message that carries a wire: the MT103. Think of it as a shipping label attached to your money, it travels with the payment and tells every bank along the way who's sending it, who should get it, and how much.
If you've ever wired money to buy something abroad, pay a supplier, or send a large gift to family overseas, an MT103 was created somewhere behind the scenes, even if you never saw it yourself.
Think of it like a package
Before the "shipping label" (the payment details), the message has a few layers of packaging around it, similar to how a package has a box, a shipping label, and sometimes a customs form:
Most of that packaging is handled automatically by the bank's systems. The part people actually mean when they say "MT103" is the payment details section, made up of labeled fields, kind of like a form with labeled boxes: "amount here," "recipient name here," and so on.
The fields that matter, in plain English
| Label | What banks call it | What it actually means |
|---|---|---|
:20: | Sender's Reference | A tracking number for this specific payment, like a package tracking ID |
:23B: | Bank Operation Code | Almost always just says "this is a standard payment" |
:32A: | Value Date / Currency / Amount | When the money moves, in what currency, and how much |
:50: | Ordering Customer | Who's sending the money, name and account |
:53: / :54: | Correspondent banks | The "connecting flights" the money takes if the two banks don't deal with each other directly |
:57: | Account With Institution | The recipient's bank |
:59: | Beneficiary Customer | Who's receiving the money, name and account |
:70: | Remittance Information | A note, like "invoice #4471" or "birthday gift" |
:71A: | Details of Charges | Who pays the wire fee: the sender, the receiver, or split between both |
A real world example
Let's say a small UK company, Northwind Trading, needs to pay a supplier in Germany, Hansa Maschinen, $48,500 for a shipment of machine parts. Their banks don't have a direct relationship, so the payment needs a middleman bank (a correspondent) to help it along, kind of like a connecting flight instead of a direct one.
Here's roughly what that message looks like:
Tracking number: REF20260813001
Payment type: Standard payment
When / currency / how much: Aug 14, USD 48,500.00
From: Northwind Trading Ltd, London, UK
Connecting bank: Chase, New York
Recipient's bank: Deutsche Bank
To: Hansa Maschinen GmbH, Frankfurt, Germany
Note: Invoice 4471-B, machine parts
Who pays the fee: Split between sender and receiver
In plain terms: Northwind is paying Hansa $48,500, the payment gets routed through Chase in New York as a middleman before landing at Deutsche Bank in Germany, and both companies split the wire fee.
Why the "connecting bank" matters
Just like a flight from London to Frankfurt might need a connection if there's no direct route, a payment between two banks that don't have a relationship needs to pass through a bank that does business with both of them. That's the correspondent bank.
When that happens, a second message travels alongside the first one, it's like a heads up sent ahead saying "expect this payment and here's where the actual funds are coming from." That message makes sure the money actually arrives, while the first message (the MT103) carries the details about who it's for.
What's next
Next time, we'll do the same walkthrough for an ACH payment, the kind that pays your salary or charges your Netflix subscription, and see how reading one payment out of a batch of ten thousand is a very different problem than reading a single wire.