A reserve currency is a foreign currency that central banks and governments hold in large quantities so they can settle international trade, pay foreign debts, and steady their own exchange rates. The U.S. dollar dominates this role, making up about 57 percent of the world’s allocated foreign exchange reserves as of mid-2025, with the euro a distant second near 20 percent.1IMF Data. IMF Data Brief: Currency Composition of Official Foreign Exchange Reserves The dollar’s share has drifted down slowly over the past two decades, but no single challenger has taken its place.
What Central Banks Use Reserve Currencies For
Paying for Cross-Border Trade
Countries that trade with each other need a common unit to price and pay for goods. Oil, metals, agricultural commodities, and many manufactured goods are priced in a major reserve currency no matter where the buyer or seller sits. That removes the need for dozens of bilateral currency conversions and makes pricing predictable. The arrangement reinforces itself: because so many existing contracts use the dollar or euro, new contracts default to the same currencies.
Energy trade is the clearest example. After the oil price spikes of the 1970s, petroleum exporters accumulated large dollar surpluses because oil sales were denominated in dollars. Those “petrodollars” flowed back into dollar-denominated investments, deepening U.S. capital markets and locking in the dollar’s role in energy trade.2International Monetary Fund. Money Matters: An IMF Exhibit – Reinventing the System (1972-1981) Some oil exporters have started settling energy trades in other currencies, but the pattern persists.
Denominating International Debt
Governments and companies often borrow from foreign investors in a major reserve currency rather than their local money. Borrowers reach a deeper pool of lenders, and lenders get repaid in a currency they already trust. Emerging-market governments routinely issue dollar-denominated bonds for this reason. The trade-off is real: if the borrower’s local currency weakens against the dollar, the cost of servicing that debt climbs sharply.
Managing the Exchange Rate
Central banks hold reserves so they can step into currency markets when the local money swings too hard. If the domestic currency is falling fast, the central bank sells dollar or euro reserves and buys the local currency to prop it up. If the currency has strengthened enough to hurt exports, it can do the reverse. Doing this at meaningful scale requires large, liquid stockpiles of foreign currency and foreign-government bonds.
How much reserve to hold is a running question. The most common benchmark is import coverage, used by roughly 78 percent of central banks surveyed by the World Bank, followed by ratios of reserves to short-term external debt and the IMF’s own Assessing Reserve Adequacy framework.3World Bank. Inaugural RAMP Survey on the Reserve Management Practices of Central Banks: Results and Observations
What Makes a Currency Reserve-Worthy
No formal checklist crowns a reserve currency, but a few traits show up every time. Central banks are cautious institutions, and they need reserves that hold value and can be moved quickly.
Deep, Liquid Markets
A central bank holding billions in a foreign currency needs to buy and sell without pushing the price around. That requires deep financial markets with high trading volumes. The U.S. Treasury market is the clearest example. It remains the world’s largest and most liquid bond market, which is precisely why central banks gravitate toward it.4Federal Reserve Bank of New York. Measuring Treasury Market Liquidity Thin or volatile markets simply cannot absorb the scale of reserve management transactions.
Economic and Institutional Stability
Reserve holders want their assets to hold value across decades. That favors currencies from countries with low inflation, disciplined fiscal policy, and dependable legal systems. Property rights and contract enforcement matter because a reserve holder is, in effect, a long-term creditor. If laws change unpredictably or assets can be frozen or seized without recourse, the currency’s appeal falls sharply.
Capital Account Openness
Open capital accounts help, but full liberalization is not strictly required. China’s renminbi has been included in the IMF’s SDR basket and held as a reserve asset despite significant Chinese capital controls, including licensing requirements, quantitative limits, and exchange-rate management. IMF research has found that some capital account openness is necessary, but full convertibility is not a prerequisite in the early stages of reserve currency adoption.5IMF eLibrary. Capital Account Opening and Capital Flow Management
Controls do cap a currency’s ceiling, though. Central banks want confidence that they can move money in and out without surprise restrictions. China’s controls are a major reason the renminbi’s reserve share has stalled around 2 percent despite China being the world’s second-largest economy. Fully convertible currencies like the dollar and euro keep a structural edge because holders face no restrictions when they need to liquidate.
The IMF’s Freely Usable Currency Standard
The IMF applies a formal test when deciding which currencies belong in the SDR basket, and central banks treat that designation as a signal of reserve-worthiness. Under the IMF’s Articles of Agreement, a “freely usable” currency is one widely used to make payments for international transactions and widely traded in the principal exchange markets.6International Monetary Fund. Articles of Agreement of the International Monetary Fund The issuing country must also have ranked among the world’s largest exporters over a five-year period. There are no preset numerical thresholds; the IMF’s Executive Board uses judgment informed by quantitative indicators.7International Monetary Fund. Q and A on 2015 SDR Review
Which Currencies Central Banks Actually Hold
The IMF tracks the composition of global reserves through its COFER database. In the second quarter of 2025, the U.S. dollar’s share of allocated reserves stood at 56.32 percent. Much of the decline from prior quarters reflected exchange-rate movements rather than active diversification. Adjusted for currency fluctuations, the dollar’s share was closer to 57.67 percent.8International Monetary Fund. Dollar’s Share of Reserves Held Steady in Second Quarter When Adjusted for FX Moves
The euro held 21.13 percent in raw terms, closer to 19.96 percent at constant exchange rates.8International Monetary Fund. Dollar’s Share of Reserves Held Steady in Second Quarter When Adjusted for FX Moves The Japanese yen, British pound, and Chinese renminbi fill out the traditional reserve currencies. The renminbi sat at 2.12 percent, essentially unchanged from the prior quarter.1IMF Data. IMF Data Brief: Currency Composition of Official Foreign Exchange Reserves Nontraditional reserve currencies have picked up ground quietly: the Canadian dollar held roughly 2.6 percent and the Australian dollar about 2.1 percent of global reserves by mid-2025.
Central banks spread their reserves across these currencies to avoid overexposure to any single economy. The slow drift away from dollar dominance over the past 20 years has not produced a dramatic shift. The dollar’s lost share has been spread thinly across a wider range of currencies rather than absorbed by one challenger.
How the Dollar Became the Anchor
In July 1944, delegates from 44 nations met in Bretton Woods, New Hampshire, and designed a new international monetary system. The agreement created the International Monetary Fund and the World Bank and set up fixed exchange rates anchored to the U.S. dollar, which was itself convertible into gold at $35 per ounce.9Office of the Historian. Bretton Woods-GATT, 1941-1947 The United States held roughly two-thirds of the world’s monetary gold at the time, which made the promise credible.
The system carried a built-in tension that economist Robert Triffin identified in 1960. For the world to have enough dollar liquidity, the United States had to run persistent trade deficits, pumping dollars abroad. But the more dollars piled up overseas, the less credible the promise to convert them into gold became. If the U.S. stopped running deficits, global liquidity would dry up; if the deficits continued, confidence in the dollar would erode.10International Monetary Fund. Money Matters: An IMF Exhibit – The Importance of Global Cooperation, System in Crisis (1959-1971)
By the late 1960s, foreign dollar holdings far exceeded U.S. gold reserves. In August 1971, President Nixon suspended the dollar’s convertibility into gold, effectively ending the Bretton Woods system.11Federal Reserve History. Nixon Ends Convertibility of U.S. Dollars to Gold and Announces Wage and Price Controls By 1973, floating exchange rates had replaced fixed parities among major economies. The dollar stayed on top anyway, carried by the depth of U.S. financial markets, the volume of dollar-denominated trade, and the absence of a credible alternative.
Special Drawing Rights Are Not the Same Thing
The IMF created the Special Drawing Right in 1969 as a supplemental international reserve asset, designed to address concerns about whether the supply of gold and dollars would keep pace with world trade.12International Monetary Fund. Special Drawing Rights (SDR) An SDR is not a currency you can spend. It is a potential claim on the freely usable currencies of IMF member countries, essentially a line of credit that members can tap during financial stress.
The SDR’s value is based on a basket of five currencies: the U.S. dollar, euro, Chinese renminbi, Japanese yen, and British pound.13International Monetary Fund. Special Drawing Rights – IMF The IMF reviews the composition every five years to keep the weights aligned with each currency’s real importance in global trade and finance.12International Monetary Fund. Special Drawing Rights (SDR) The SDR also carries its own interest rate, calculated weekly from a weighted combination of short-term government debt rates in each basket currency.14International Monetary Fund. SDR Interest Rate Calculation
When a member needs hard currency, it can exchange its SDR allocation for freely usable currency through voluntary trading arrangements, which are bilateral agreements between the IMF and participating countries.15International Monetary Fund. Annual Update on SDR Trading Operations If voluntary arrangements fall short, the IMF can designate members with strong external positions to buy SDRs from those in need, which acts as a backstop so holders can always convert their allocations into usable money.16International Monetary Fund. Questions and Answers on Special Drawing Rights
What the Issuing Country Gets Out of It
Issuing the world’s primary reserve currency comes with tangible benefits. Because foreign governments and institutions hold vast quantities of U.S. currency and dollar-denominated bonds, the United States effectively receives what amounts to a low-interest or interest-free loan from the rest of the world. The profit a government earns from issuing currency that costs almost nothing to produce but holds face value abroad is called seigniorage, and estimates of the annual U.S. savings have been in the range of $20 billion. French finance minister Valéry Giscard d’Estaing called this advantage the “exorbitant privilege” in the 1960s.
The privilege is real but often overstated. The interest rates the U.S. pays on government debt are not consistently lower than what other creditworthy nations pay. And the flip side is structural: to supply the world with enough dollars, the United States must run persistent current account deficits, importing more than it exports year after year. That is the same tension Triffin identified in 1960, and it has never been fully resolved.10International Monetary Fund. Money Matters: An IMF Exhibit – The Importance of Global Cooperation, System in Crisis (1959-1971) The deficits that keep global dollar liquidity flowing also contribute to erosion of U.S. manufacturing competitiveness, because steady demand for dollars keeps the currency stronger than it might otherwise be.
Where the System Is Heading
Reserve status also gives the issuing country enormous leverage. After Russia’s invasion of Ukraine in 2022, Western nations froze roughly $300 billion in Russian central bank reserves. The bulk of those frozen assets were held in euros and pounds at European custodians rather than in dollars, but the coordinated G7 action sent a clear signal that reserves in Western currencies are only safe if the holder stays on good political terms with the issuers.
That episode accelerated conversations about diversification, especially among countries that worry they could face similar treatment. Central banks have leaned on gold as a hedge. In January 2026, Uzbekistan, Malaysia, the Czech Republic, Indonesia, China, and Serbia all added to their gold holdings, and the Bank of Korea announced plans to incorporate gold-backed ETFs into its reserves for the first time since 2013. China has bought gold for 15 consecutive months, lifting gold to nearly 10 percent of its total reserves.17World Gold Council. Central Bank Gold Statistics: Momentum Eases in January While Demand Base Broadens
The expanded BRICS grouping has been the most visible force pushing for alternatives to dollar-dominated trade. Proposals include local-currency settlement mechanisms, bilateral swap lines, and a potential shared clearing unit anchored in a basket of currencies and commodities. The goal is not to swap one national currency for another but to create a neutral unit of account for trade among participating countries. Pieces of this infrastructure exist in scattered form, but no integrated clearing system has materialized yet.18Asia Times. A Stable and Smart BRICS Route to De-dollarization
Central bank digital currencies add another variable. Many countries are exploring or piloting CBDCs for cross-border payments, and global regulatory frameworks for digital finance are expected to solidify in 2026.19World Economic Forum. A Digital Economy at an Inflection Point: What to Expect for Digital Assets in 2026 Whether CBDCs eventually function as reserve assets or just as settlement tools for bilateral trade is still unclear. The dollar’s dominance is declining slowly and being replaced by fragmentation rather than a single heir. Central banks are spreading reserves across more currencies, holding more gold, and testing new settlement technologies, but the structural advantages that put the dollar on top, and have kept it there for 80 years, have proven more durable than periodic predictions of its demise.