Position Reconciliation and Nostro Reconciliation

Before diving into the reconciliation processes, it is worth being precise about what a "position" actually is in a capital markets context — because the word is used differently depending on whether you are talking to a rates trader, an equity derivatives desk, or an operations team.

A position is the net exposure that results from one or more trades in a particular instrument or risk factor. It can be expressed in several ways depending on the asset class:

• Notional: for fixed income and derivatives, the face value of the instrument. A long position in £10m notional of a UK gilt means the bank holds £10m face value of that bond. A £50m notional interest rate swap is a swap where interest is calculated on a £50m reference amount.
• Long vs short: long means the bank owns or has bought the instrument (and benefits from prices rising); short means the bank has sold the instrument without owning it (and benefits from prices falling). In derivatives, long means the bank is a receiver of the fixed leg (or equivalent); short means it pays fixed.
• DV01 (Dollar Value of 01): for interest rate positions, DV01 is a more useful risk metric than notional. It measures the change in the position's value for a one-basis-point (0.01%) move in interest rates. A DV01 of £50,000 means the position gains or loses £50,000 for every basis point move in the relevant rate. DV01 is additive across different instruments and maturities, making it the primary tool for aggregating and managing rate risk.
• Delta: for options and equity derivatives, delta measures the sensitivity of the position's value to a move in the underlying asset's price. Delta is expressed as a fraction between -1 and +1.

A trading book's position is the aggregate of all the individual trades in that book, netted appropriately. The book may hold positions in thousands of instruments simultaneously — different bonds, different swap maturities, different option strikes — and the aggregate position in each risk factor must be calculated and managed.

The front-office system — the trading system or platform where trades are captured and risk is managed — maintains a position record. The back-office system — where trades are confirmed, settled, and lifecycle-managed — maintains a separate position record. These two records should agree. When they do not, it is a position break.

Position reconciliation between front office and back office is typically run at least daily, often overnight after all trades for the day have been processed. The reconciliation compares, for each instrument or trade identifier:

• Number of trades
• Notional amounts
• Direction (buy/sell, pay/receive)
• Trade dates and maturity dates

For a derivatives book, this reconciliation runs at the trade level — each individual swap, option, or forward is compared between the two systems. For a securities book, it may run at the position level — the net holding in each ISIN (International Securities Identification Number) is compared.

What causes position breaks? The most common causes are interface failures (the feed from the front-office to the back-office system dropped a trade or corrupted its data), amendments processed in one system that were not replicated in the other, and lifecycle events (assignments, novations, partial terminations) that updated one system but not both.

Suspense accounts. When a position break is identified and cannot be immediately resolved, the item may be moved to a suspense account — a temporary holding account used to park breaks that are under investigation. Suspense accounts should be reviewed and cleared daily. A large or aged item in a suspense account is a significant risk flag.

To understand nostro reconciliation, you first need to understand how nostro accounts fit into the global payment system. Banks do not hold accounts with every other bank in the world. Instead, they use correspondent banking relationships: they hold accounts at a small number of well-connected banks in each major financial centre. These accounts are the nostro accounts.

A typical global bank might hold:

• A USD nostro at a major US correspondent bank (e.g. JPMorgan Chase or Citibank N.A.) to process US dollar payments
• A EUR nostro at a major eurozone correspondent (or directly in TARGET2, the European RTGS system, if it has direct membership)
• A GBP nostro at a UK clearing bank to process sterling payments through CHAPS
• Additional nostro accounts in other currencies — JPY, CHF, AUD — held at correspondents in those markets

Every cross-border or cross-currency payment flows through these nostro accounts. When the bank pays a dollar amount to a counterparty, it sends a SWIFT instruction to its USD correspondent, which debits the nostro and credits the recipient. When it receives a dollar payment from a counterparty, the correspondent credits the nostro.

Each business day, the correspondent bank sends a SWIFT MT940 message (end-of-day account statement) or MT950 (interim statement) to the bank. This message lists every debit and credit that occurred in the nostro account during that day, together with the opening and closing balances.

The bank's internal records — maintained by the payments and settlements systems — track what debits and credits were expected to pass through each nostro account. The nostro reconciliation matches each item on the MT940 statement against the corresponding expected item in the internal records.

Three categories of item arise:

• Matched items: the correspondent statement shows a debit or credit that exactly matches an expected item in the internal records. These require no action.
• Internal-only items: the internal records show an expected debit or credit that has not appeared on the correspondent's statement. This typically means the payment has not yet been processed — it may arrive in the next statement, or it may have failed.
• Statement-only items: the correspondent's statement shows a debit or credit that does not match any expected item in the internal records. This is potentially the most serious category — it may indicate a payment received from an unidentified source, a payment made in error, or a fraud.

The reason nostro reconciliation is so important becomes clear when you understand Herstatt risk — the risk that one leg of a settlement completes while the other does not. In 1974, the German bank Herstatt was closed by regulators at the end of the German business day. Several banks had already paid German marks to Herstatt expecting to receive US dollars in return. Because the US dollar leg had not yet settled (New York was still open), those banks lost the full dollar amount — not just a credit loss, but a complete principal loss.

Modern CLS settlement has eliminated Herstatt risk for FX trades settled through CLS. But for bilateral payments not settled through CLS, the risk remains. Nostro reconciliation is the mechanism by which the bank verifies that both legs of a transaction have settled, and identifies any cases where one leg has settled but the other has not — before that exposure becomes a loss.