How International Wire Transfers Actually Work: SWIFT, SEPA, and Correspondent Banking

Every year, trillions of pounds, dollars, and euros move around the world through the international banking system. Most of the people initiating those transfers have only a vague understanding of what actually happens between clicking "send" and the recipient seeing funds. The process is considerably more complex — and more fee-laden — than a simple account-to-account movement suggests.

Understanding how international transfers work helps explain why they sometimes take longer than expected, why the recipient sometimes receives less than you sent, and why newer services like Wise have been able to offer materially better terms than traditional banks.

The SWIFT Network

SWIFT stands for the Society for Worldwide Interbank Financial Telecommunication. It is a cooperative organisation headquartered in Belgium, owned by its member financial institutions. SWIFT provides a standardised, secure messaging network through which banks communicate payment instructions.

A crucial point that is widely misunderstood: SWIFT does not transfer money. It transfers messages — secure, standardised payment instructions telling banks to debit and credit specific accounts. The actual movement of funds occurs through correspondent banking accounts.

The SWIFT messaging standard uses:

• BIC codes (Bank Identifier Codes, also called SWIFT codes): An 8 or 11-character code identifying a specific bank and branch. Every SWIFT-connected bank has a BIC.
• IBAN (International Bank Account Number): A standardised account number format used across Europe and many other jurisdictions. Required for payments within SEPA; increasingly used for SWIFT transfers.
• Message types: Standardised SWIFT message formats (MT103 for customer credit transfers, MT202 for bank-to-bank transfers, and so on). SWIFT is transitioning to ISO 20022, a richer message standard that carries more payment data.

The Correspondent Banking Network

Most banks do not have direct bilateral relationships with every other bank in the world. Instead, they maintain relationships with a smaller number of large correspondent banks — typically major global banks such as Citibank, HSBC, JP Morgan, Deutsche Bank, BNY Mellon, and Standard Chartered — that can access currencies and banking systems in markets around the world.

Nostro and Vostro accounts: The mechanics work through paired accounts. When Bank A in the UK has a correspondent relationship with Bank B in the UAE, Bank A holds an account at Bank B denominated in AED (Bank A's "nostro" account — "our money with you"). Bank B sees this as a "vostro" account — "your money with us." When Bank A needs to make a payment in AED to a recipient in the UAE, it instructs Bank B (via SWIFT) to debit its nostro account and credit the recipient's account.

The multi-hop problem: Small banks may not have direct correspondent relationships with banks in all markets. A transfer from a small UK building society to a bank in Vietnam, for example, might transit through three or four correspondent banks:

1. The UK building society instructs its UK correspondent (e.g., Barclays)
2. Barclays instructs its USD correspondent in New York (e.g., JP Morgan)
3. JP Morgan instructs its banking partner in Singapore
4. The Singapore bank instructs the Vietnamese bank

Each step in the chain takes time (processing during that bank's working hours), and each bank may deduct a correspondent fee from the transfer amount.

The Hidden Fee Problem

This is where the cost of traditional bank international transfers becomes opaque. The sending bank's fee is disclosed upfront. But correspondent banks along the route can deduct fees from the transfer amount — which is why the recipient sometimes receives less than the sender sent, even after the sender has paid the disclosed fee.

The OUR/BEN/SHA instruction: To control how fees are allocated, international transfers include a charges instruction code:

• OUR: The sender bears all charges at every point in the chain. The recipient receives the full amount sent.
• BEN: The beneficiary bears all charges. Fees are deducted from the transfer amount at each correspondent bank.
• SHA: Shared — the sender pays the sending bank's fees; the recipient bears any intermediate correspondent bank fees.

For transfers where you need the recipient to receive a precise amount (e.g., a property purchase deposit of exactly £50,000), always specify OUR. This is more expensive for the sender but eliminates uncertainty about the amount received.

Why Transfers Get Delayed

A standard international SWIFT transfer typically takes two to five business days. Common causes of delay:

Time zone and working-hour differences: A payment sent from the UK at 4pm may not be processed by a US correspondent bank until the following morning. If it then needs to reach an Asia-Pacific bank, add another cycle.

OFAC compliance screening: The US Office of Foreign Assets Control (OFAC) maintains sanctions lists. Any dollar-denominated transaction — even between two non-US parties, if it transits through a US correspondent bank — must be screened against OFAC lists. US correspondent banks are legally required to conduct this screening. A name match (even a false positive) triggers a manual review, potentially delaying the transfer by days.

AML holds: Any large or unusual transaction may be flagged for manual compliance review at any bank in the chain. Banks receiving transfers that do not match the customer's known profile may request documentation from the originating bank.

Cut-off times: Banks have cut-off times after which payment instructions received that day are processed the following business day. Missing a cut-off by minutes adds a day.

Public holidays: A public holiday in any country in the payment chain adds a day. If your transfer to the UAE arrives on a Friday (a weekend in the UAE), it may not process until Sunday.

Beneficiary information errors: If the IBAN or BIC contains an error, the payment may be returned or held at an intermediate bank while corrections are made. Always verify recipient details before sending.

SEPA: The European Alternative

Within the SEPA (Single Euro Payments Area), international EUR payments work very differently. SEPA covers 36 countries — all EU member states plus Norway, Iceland, Liechtenstein, Switzerland, and the UK (which retained SEPA access post-Brexit as a third country).

SEPA Credit Transfers: EUR transfers within the SEPA area go through a central clearinghouse (Target2 or EBA Clearing's STEP2), not through correspondent banks. They are typically settled same-day or next-day. They cost very little — typically £0–5 from a bank, and fractions of a penny from digital providers.

SEPA Instant: An enhanced SEPA rail providing payments in under ten seconds, available 24/7/365. Available to banks that have joined the scheme.

Post-Brexit: UK payment providers retained SEPA access as third-country participants — UK banks can still send and receive SEPA Credit Transfers and SEPA Instant. What changed is that the UK lost certain single-market benefits (for example, UK businesses can no longer collect SEPA Direct Debits from EU bank accounts, withdrawn in 2021), and UK PSPs may apply correspondent-style charges that EU-based providers do not. Services like Wise maintain their own European bank accounts and effectively provide low-cost SEPA-equivalent transfers for their customers.

CHAPS: UK Domestic Same-Day Payments

The Clearing House Automated Payment System (CHAPS) is the UK's same-day sterling payment system. Used for:

• Property purchase completions
• Large business-to-business payments
• Court judgments and legal settlements

CHAPS payments settle on a gross real-time basis throughout the day (Real-Time Gross Settlement, RTGS). They are expensive relative to Bacs or Faster Payments (typically £15–35 per payment from a bank) but are guaranteed to settle the same day if sent before the cut-off (typically 5pm).

For property completions, CHAPS is the required payment method — certainty of settlement on a specific day is essential in conveyancing.

SWIFT gpi: The Upgrade

SWIFT gpi (Global Payments Innovation) is a major enhancement to the SWIFT network, adopted by most large banks since its launch in 2017. Key improvements:

Same-day settlement: SWIFT gpi aims to complete cross-border payments within the same day, with end-to-end tracking.

Track and trace: Like a parcel courier tracking number, SWIFT gpi provides a unique payment reference (UETR — Unique End-to-end Transaction Reference) that both sender and recipient's banks can use to check the status of a payment at any point in the chain.

Fee transparency: gpi-compliant banks must disclose deducted correspondent fees in the tracking data, making the total cost visible.

Stop and recall: SWIFT gpi includes a mechanism for recalling or stopping a payment in transit — useful if an error is discovered after sending.

Most major international bank transfers now use SWIFT gpi. If your bank offers a transfer tracking reference, it is likely a gpi transfer.

The New Payment Rails

SWIFT's dominance of international payments is being challenged by newer infrastructure:

Wise's proprietary network: Rather than routing payments through correspondent banks, Wise operates its own local bank accounts in each major currency market. A Wise transfer from GBP to USD does not travel internationally — Wise debits your GBP from its UK pool and credits USD from its US pool, balancing the two pools periodically. This eliminates correspondent bank intermediaries and their fees.

RippleNet and blockchain-based rails: Ripple's network has attracted some banks as a correspondent banking alternative, offering near-instant, low-cost settlement. Adoption among tier-one banks has been slower than Ripple projected, but niche and corridor-specific use cases have developed.

Central Bank Digital Currencies (CBDCs): Multiple central banks are piloting CBDCs that could allow bank-to-bank settlement at the central bank level, bypassing correspondent networks. The Bank of England, ECB, and People's Bank of China are among those running advanced pilots. Widespread commercial deployment is still several years away.

ISO 20022: While not a new network, ISO 20022 is a data standard replacing older SWIFT message formats. It carries richer, more structured data — including full beneficial ownership details — which makes compliance screening faster and reduces delays caused by incomplete information. SWIFT is migrating the global financial system to ISO 20022 through 2025–2027.

Practical Guidance for Large International Transfers

When sending a significant sum internationally:

1. Verify the recipient's details twice: IBAN, BIC, and account name. An error means the payment may be returned slowly or, in some jurisdictions, lost.
2. Use OUR charges if sending a specific amount: Ensure the recipient receives exactly what you intend.
3. Send early in the day: Avoid cut-off times.
4. Provide a clear payment reference: Describing the purpose helps compliance teams at correspondent banks understand the transfer and reduces the probability of a hold.
5. Notify your bank in advance for large transfers: A call or message to your bank before sending a large sum (£50,000+) reduces the chance of an automatic AML hold.
6. For critical-timing transfers: Use SWIFT gpi-enabled transfers or specialist FX brokers who can track the payment through the chain.
7. Consider Wise or specialist FX brokers: For amounts above £5,000, the cost savings versus bank SWIFT can be significant. For amounts above £50,000, specialist FX brokers add forward contract capability and personalised service.

Compliance and Important Caveats

All international transfers must be to verified recipients for legitimate purposes. Anti-Money Laundering regulations require both sending and receiving banks to conduct due diligence. Providing false information on a payment instruction is a criminal offence. OFAC sanctions are US law but affect any USD-denominated transaction globally — ensure the recipient and any intermediaries are not on sanctions lists before sending. Regulations, SWIFT gpi implementation status, SEPA access arrangements for the UK, and correspondent banking relationships change regularly. This guide reflects general practice as of 2026 and is for information purposes only; it does not constitute financial or legal advice.

How Global Investments Can Help

Global Investments works with internationally mobile clients making significant cross-border transfers — for property purchases, investment, and wealth management. We can introduce you to specialist FX brokers and international payment specialists who provide competitive rates, transfer tracking, and forward contracts for large transactions, along with the professional support that consumer platforms cannot match. Contact us when planning a significant international transfer.