Correspondent banking is an arrangement where one bank holds accounts and provides payment services for another bank, usually to reach markets or currencies it cannot serve on its own. It is what lets money cross borders, but because the correspondent often cannot see the underlying customers, it carries some of the highest AML risk in the system.
What is correspondent banking?
No single bank has branches everywhere or accounts in every currency. Correspondent banking solves that by letting a respondent bank open an account at a correspondent bank that does have reach in the place or currency it needs. The respondent's customers can then send and receive cross-border payments through the correspondent's network. The account the respondent holds for this is often called a nostro or vostro account, depending on whose books you read it from.
The AML challenge is structural. The correspondent has a direct relationship with the respondent bank, but usually no direct relationship with the respondent's underlying customers. It is processing payments for people it never onboarded, in jurisdictions it may not know well, relying on the respondent to have done proper due diligence. That is why regulators treat correspondent relationships as inherently higher risk and expect enhanced due diligence on the respondent.
For an AML team, the key idea is layered visibility. Each bank sees only its slice of the chain, so a payment can pass through several institutions with no one party seeing the full picture of who is paying whom and why.
How a correspondent payment flows
A cross-border transfer typically hops through more than one institution before it lands:
- OriginCustomer instructs a payment A customer of the respondent bank sends money abroad in a currency their bank cannot settle directly.
- RouteRespondent uses its correspondent The respondent instructs its correspondent, which holds the account and the currency network to move it.
- SettleCorrespondent moves the funds The correspondent debits the respondent's account and pays the beneficiary's bank, often via another correspondent.
- DeliverBeneficiary is credited The beneficiary bank credits the recipient, completing a chain no single bank saw end to end.
Who is involved?
Who | Their role |
The respondent bank | Holds the underlying customer relationship and asks the correspondent to move money on its behalf. |
The correspondent bank | Provides the account, currency access, and payment rails; owes enhanced due diligence on the respondent. |
The underlying customer | The respondent's client whose payment travels the chain, invisible to the correspondent. |
The beneficiary bank | Credits the final recipient, often at the far end of a multi-hop route. |
What it looks like in practice
A small importer banks with a regional institution that has no presence in the currency it needs to pay an overseas supplier. Its bank, the respondent, routes the payment through a large global bank, the correspondent, that holds the currency and the network to settle it.
The correspondent debits the respondent's account and forwards the funds toward the supplier's bank. From the correspondent's seat, it sees a payment instruction from a respondent it onboarded, but it never met the importer, never verified the supplier, and relies entirely on the respondent's controls. If the respondent's due diligence is weak, illicit funds can ride the same rails looking exactly like the importer's legitimate trade payment.
Why it matters to operators
Correspondent banking concentrates risk because a single relationship can carry the aggregated activity of thousands of unseen customers. If the respondent onboards weakly or serves high-risk sectors, the correspondent inherits that exposure without visibility into it. This is a classic route for layering, sanctions evasion, and moving proceeds across borders, which is why it draws heavy regulatory attention and steep penalties when controls fail.
The practical response is enhanced due diligence on the respondent: understanding its ownership, its own AML program, the markets and customer types it serves, and whether it in turn provides accounts to other institutions. Weak oversight has driven a wave of de-risking, where correspondents exit whole regions rather than manage the risk, cutting off legitimate access to the financial system in the process.
What to watch in the data
- Nested access. Signs the respondent is passing correspondent services on to other banks or institutions it does not fully disclose.
- Jurisdiction mismatch. Payment volumes or counterparties in higher-risk countries that do not fit the respondent's stated business.
- Opaque originators. Payment messages with missing, generic, or inconsistent originator and beneficiary details.
- Turnover out of line. Activity through the account far larger or more volatile than the respondent's size and profile would suggest.
- Message stripping. Altered or truncated names, references, or countries that hint at attempts to defeat screening downstream.
Quick questions
What is the difference between a nostro and a vostro account?
They are two views of the same account. A nostro is "our account with you" from the respondent's perspective; a vostro is "your account with us" from the correspondent's. The label just depends on whose books you are reading.
Why is correspondent banking considered high risk?
The correspondent processes payments for the respondent's customers without having onboarded them. It relies on the respondent's due diligence and often serves multiple jurisdictions, so bad actors can hide inside legitimate flows the correspondent cannot see directly.
What is enhanced due diligence on a respondent?
It means going beyond basic checks to understand the respondent's ownership, AML program quality, customer base, jurisdictions, and whether it offers nested access to other institutions, so the correspondent can gauge the risk it is taking on.
How does de-risking connect to this?
When the cost or difficulty of managing correspondent risk is too high, banks sometimes exit entire markets or respondent categories wholesale. That is de-risking, and while it lowers a bank's exposure, it can cut off legitimate access to cross-border payments.
Where does nesting fit in?
Nesting is when the respondent lets its own account be used by other banks or their customers, hiding the true originator one more layer down. It is a specific, elevated risk within correspondent relationships and often has to be flushed out through due diligence.
What to know alongside Correspondent banking
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