Loro, mirror and shadow accounts

A loro account is a bank account held by a bank for another bank, and the word comes from the Italian for theirs, because the account holds their money. A nostro account is our account held at another bank, and a vostro account is your account held on our books, so a nostro for one bank is a vostro for the other, and a loro is the same idea seen from the bank that holds the account for a third bank. The four terms describe the same balance from four viewpoints, and confusing them causes reconciliation errors. Source: Bank for International Settlements, Committee on Payments and Market Infrastructures; SWIFT correspondent banking guidance. The mechanism is that every correspondent balance exists twice, once on each bank books, and the two records must agree. Bank A holds a USD nostro account at Bank B in New York with a balance of USD 5 million, and Bank B holds the same account as a USD vostro account for Bank A, also USD 5 million. When Bank A pays USD 100,000 to a customer of Bank B, Bank A debits its customer and credits its nostro, so the nostro falls to USD 4. 9 million, and Bank B debits its vostro and credits its customer, so the vostro falls to USD 4. 9 million. The mirror and the shadow are updated at the same time, so all four records agree, and the daily reconciliation proves it. A worked example with a break shows why the mirror matters. Bank A nostro balance is USD 5 million on Monday morning, and Bank A sends three payments totalling USD 300,000, so the mirror falls to USD 4. Bank B statement arrives on Tuesday and shows a balance of USD 4. 8 million, a difference of USD 100,000. The break is USD 100,000, the cause is a rejected payment, and the fix is to reverse the nostro debit at Bank A and to resend the payment with the correct field. The mirror made the break visible on the day it happened, rather than at the month end, because the mirror is updated from the payment instruction, not from the statement. The parties are the account holding bank, the account owning bank, and any third bank that uses the account through a nested relationship. A nested correspondent account is a loro account held for a bank that is itself a correspondent of the holding bank, so Bank C holds an account at Bank A, and a payment from Bank C to Bank B passes through Bank A loro account. The nested bank must be screened and monitored, because the holding bank bears the compliance risk for the nested customer, and the Wolfsberg Correspondent Banking Principles set the standard for due diligence on nested relationships. A payment through a nested account must carry the full party data, because the holding bank must be able to screen the underlying customer, not just the immediate correspondent. Failure in loro, mirror and shadow accounts is a reconciliation break, and the break has a standard handling. A real versus mirror break is a difference between the actual nostro balance on the statement and the mirror balance on the bank books, and it is investigated by matching entries, one by one, until the unmatched entry is found. A second cause is a fee or a charge deducted by the correspondent, which the bank did not expect, and the fix is to post the fee to the correct expense account. A third cause is a duplicate posting, where the same payment is debited twice, and the fix is a reversing entry, not a deletion. The effect on the bank, the customer and operations is that loro, mirror and shadow accounts are the control for cross-border payments. For the customer, a nostro break can delay a payment, because the bank cannot be sure the funds are available, and the customer must be told the payment is held for reconciliation. For operations, the daily nostro reconciliation is a regulatory expectation, and an unreconciled nostro is a finding in an audit, because it means the bank cannot prove where its money is. A business analyst must specify the mirror update rule, the statement matching rule, the ageing rule and the escalation for every nostro account. For a business analyst, product owner or subject matter expert, the test is to draw the four views of one correspondent balance and to state which system holds each one. Ask which account is debited and which is credited for a payment, a return and a fee, and how the mirror is updated at each step. Ask who owns a nested account, what due diligence was done, and what party data must travel with the payment. The ISO 20022 camt.052 and camt.053 messages report the nostro balance, and the MT940 and MT942 messages did the same in the MT world, so the reconciliation can be automated if the mapping from the statement to the mirror is specified correctly. Two mistakes are common and must be avoided. The first is to call a mirror account a real account, which overstates the bank assets, because the mirror is a copy, not a separate balance, and counting both double counts the money. The second is to reconcile the nostro only at the month end, which lets a break age for weeks, and the payment that caused it may be impossible to recall by then. The correct design is to update the mirror from the payment instruction in real time, to match the statement daily, to age breaks from the day they appear, and to escalate a break that is older than the scheme timeline, because a recall or a return has a deadline, and a late discovery is a lost recovery. Takeaway: a nostro is our account at another bank, a vostro is your account on our books, a loro is an account held for another bank, and a mirror or shadow account is a copy kept for reconciliation. The four records of one balance must agree, and a difference is a break that is investigated entry by entry, with value-date timing aged separately from real errors. Further reading: Bank for International Settlements, Committee on Payments and Market Infrastructures, A glossary of terms used in payments and settlement systems; Wolfsberg Group, Correspondent Banking Due Diligence Questionnaire and Principles. Last reviewed 7 November 2026.