FX intervention is an official purchase or sale of currencies intended to influence an exchange rate or conditions in the foreign exchange market. For a currency trader or researcher, the distinction between the trade, its funding and its policy purpose matters: an official FX transaction need not be intervention, and intervention need not produce a lasting change in the exchange rate.
Which currency is the authority buying?
Buying the domestic currency and selling foreign currency creates demand for the domestic currency. Selling domestic currency to buy foreign currency works in the opposite direction. These are the intended directions of pressure, not guaranteed price outcomes. The New York Fed’s operational explanation describes both directions and distinguishes transactions for the Federal Reserve from those it executes as fiscal agent for the US Treasury. The legal authority and the balance sheet bearing the position depend on the institution.
An authority may seek to support a currency, resist appreciation or restore orderly trading. It may also trade currencies to serve government customers or manage its reserve portfolio. The RBA’s current operations page separates these routine transactions from intervention. A large official purchase alone does not establish the policy motive.
Follow the settlement entries
Consider a fictional central bank buying USD 100 from a domestic bank at 1.50 domestic currency units per USD. Assume it pays by crediting that bank’s domestic settlement account at the central bank. Exclude fees, valuation changes and all other operations. At settlement:
The central bank gains USD 100 of foreign assets, worth 150 domestic units at the transaction rate. Its domestic settlement liabilities increase by 150. The bank selling the dollars receives the matching settlement balance. The foreign assets are assets of the central bank; the domestic settlement balances are its liabilities. “Reserves” can refer to either foreign reserve assets or commercial banks’ balances at the central bank, so specify which one is meant.
Original synthetic ledger. Entries are changes, not totals. The purchase settles before the illustrated liquidity offset; fees, valuation changes and other operations are excluded.
Sterilisation offsets the intervention’s effect on domestic liquidity. In this example, the central bank could sell existing domestic securities for 150 domestic units, with payment reducing bank settlement balances by 150. The combined change in settlement balances is zero, while the acquired USD 100 remains on its asset side. The central bank has changed the composition of its assets.
This securities sale is one simplified mechanism, not a universal balance-sheet or legal regime. The RBA’s explanation of intervention, last updated July 2020, describes offsetting domestic money-market transactions and FX swaps. The choice of instrument, account structure and monetary operating framework matters. Removing a liquidity effect does not mean the FX trade has been cancelled, nor does an unoffset settlement-balance increase mechanically determine bank lending or inflation.
A ledger does not establish policy effectiveness
Intervention can alter dealers’ inventories and convey information about the authority’s intentions. Its effects depend on market depth, expectations and the credibility of the wider policy setting. Neither sterilised nor unsterilised intervention guarantees a permanent exchange-rate effect.
For empirical work, keep the transaction date, settlement date, announcement time and disclosure time distinct. The RBA publishes intervention data with a lag. Using a later disclosure as if traders knew it when the trade occurred would introduce look-ahead bias.
A fall in the domestic currency after a support operation does not by itself show failure: the currency might have fallen further without it. Equally, a rally after an operation does not isolate the intervention’s effect from simultaneous news. The RBA’s effectiveness discussion emphasizes this missing counterfactual. A useful study therefore starts with the stated objective and the identification problem, rather than treating the cash-flow identity as a forecast.
Sources
- Federal Reserve Bank of New York, Foreign Exchange Operations: trade direction, institutional authority and the distinction from customer transactions.
- Reserve Bank of Australia, International Market Operations: intervention objectives, routine FX business, foreign assets and lagged intervention disclosure.
- Reserve Bank of Australia, The Exchange Rate and the Reserve Bank’s Role in the Foreign Exchange Market, §§7–8: sterilisation mechanisms, signalling and the difficulty of measuring effectiveness; page last updated July 2020.
- John C. Hull (2018), Options, Futures, and Other Derivatives, 9th ed., Global Edition, §5.10, pp. 139–140: explicit domestic-per-foreign currency units. The intervention ledger here is an original synthetic example.