A reserve currency is simply the money that other countries’ central banks choose to hold in bulk. They keep it for emergencies, for defending their own currency, and for paying foreign debts. The US dollar has held that job for most of the last eighty years, and the way it got there says more about its behaviour today than any chart does.
What “reserve currency” actually means
Three roles tend to travel together. A reserve currency is held by central banks. It is used to invoice and settle trade between countries that have nothing to do with the issuer. And it is the currency in which a large share of international loans and bonds are written.
None of these is ordained by law. They are habits, reinforced because everyone else shares them. If most of your customers, suppliers and lenders already use dollars, using anything else costs you extra conversions. Economists call this a network effect, and it is the main reason reserve status is so sticky.
Three dates that did most of the work
The dollar’s rise came in steps, and a short timeline covers the ones that mattered.
- July 1944. Delegates from 44 nations met at Bretton Woods, New Hampshire. The dollar was fixed to gold at $35 an ounce, and other currencies were pegged to the dollar within a 1 percent band (Federal Reserve History). Every other member’s exchange rate was now defined against one currency. That is a powerful way to make a currency central.
- 15 August 1971. President Nixon suspended the dollar’s convertibility into gold (US State Department, Office of the Historian).
- March 1973. Six European Community members tied their currencies together and floated them jointly against the dollar, which effectively ended the Bretton Woods fixed-rate system.
Here is the interesting part. The gold link was cut, the fixed rates collapsed, and the dollar stayed on top anyway. The system that made it dominant was gone, but the habits it created, along with deep US financial markets, kept going.
The numbers, as of November 2026
Start with reserves. The IMF publishes the currency breakdown of official reserves, known as COFER. Its release for the second quarter of 2026 put the dollar at 56.70% of allocated reserves, down from 57.18% in the first quarter. The euro was 20.60% and the yen 4.96%.
That is lower than the long-run picture. A Federal Reserve note from 2023 gives the dollar’s share as 71% in 2000 and 58% in 2022. So the share has drifted down by roughly fourteen percentage points since 2000 (71 minus 56.70 is 14.3). A slow drift, not a collapse. Quarter-to-quarter movements are also partly valuation effects: when the dollar weakens, the dollar value of a euro-denominated reserve pile rises, and the share of euros looks bigger without anyone buying a thing.
Reserves are only one view. In trading, the dollar is even more dominant. The Bank for International Settlements surveyed foreign exchange turnover in April 2025 and found $9.6 trillion changing hands on an average day. The dollar was on one side of 89.2% of trades, up from 88.4% in 2022.
Why do those shares not sum to 100%? Because every trade has two currencies, so the shares of all currencies add up to 200%. Subtract the dollar’s 89.2 and 110.8 percentage points are left for every other currency in the world combined. Roughly speaking, the dollar appears in nine out of every ten trades. The euro appears in 28.9%, the yen in 16.8%, sterling in 10.2% and the Swiss franc in 6.4%.
Why the dollar, and not something else
Several reasons stack up, and none of them is sufficient alone.
Depth. The US government borrows in dollars on a huge scale, so there is a large, liquid market in which a central bank can park hundreds of billions and sell it quickly without moving the price. Few other places offer that combination.
Habit. The Fed note reports that about 60% of cross-border bank claims and liabilities were in dollars in 2022, a share broadly stable since 2000, and that the dollar has held roughly 70% of foreign-currency debt issuance since 2010. Borrowers want to match what their lenders have. Lenders want to lend what they can easily refinance.
Trade invoicing. The same Fed note shows dollar invoicing averaging 96% in the Americas and 74% in Asia-Pacific over 1999 to 2019. A Thai exporter selling to a Brazilian buyer will often quote in dollars even though neither country is the United States.
Rule of law and open capital markets. Holders need to believe they can get their money out. That is a matter of institutions, not slogans.
Rivals each lack something. The euro area has a big economy but no single government bond market. The yen has a deep market but a small share of invoicing outside Japan. China’s renminbi faces capital controls. Nobody can say how long this ranking will last, and this article won’t guess.
What it does to the money you convert
This is where the abstract turns into pennies. Many currency pairs rarely trade directly. If you convert Brazilian reais to Thai baht, the underlying market often routes through dollars: reais into dollars, then dollars into baht. A currency in that role is called a vehicle currency.
A worked example, with made-up rates (illustrative, not real quotes). Say 1 BRL buys 0.18 USD, and 1 USD buys 32 THB. Start with 1,000 BRL.
- 1,000 BRL x 0.18 = 180 USD
- 180 USD x 32 = 5,760 THB
The implied direct rate is 5.76 THB per real. Now suppose each leg carries a 0.25% margin (illustrative again). The calculation becomes 1,000 x 0.18 x 0.9975 x 32 x 0.9975, which comes to about 5,731 THB. You are about 29 baht short, or 0.5%. Two legs, two margins. A pair that trades directly in decent volume can avoid one of them, but for smaller currencies the dollar route is often the cheapest path anyway, because that is where the liquidity is.
There is a second, quieter effect. Because so many debts around the world are owed in dollars, a stronger dollar makes those debts heavier for borrowers who earn in other currencies. That is part of why emerging-market currencies tend to come under pressure when the dollar rallies. For a family sending money home, the practical consequence is visible on pairs like USD to INR or USD to MXN: the rate moves for reasons that have as much to do with global dollar demand as with the local economy. You can browse a whole row of dollar pairs on the US dollar page.
Does reserve status make the dollar safe?
Not in the sense of a fixed price. Reserve status means demand is broad and markets are deep. It does not stop the dollar from rising or falling against other currencies, sometimes sharply. Nobody knows what the next decade holds, and anyone offering a confident forecast is selling something.
Put it more narrowly. Reserve status lowers the cost of using dollars: tighter spreads, more providers, more routes. If you hold dollars, you can usually find someone to trade them with at any hour. That is a convenience, not a guarantee of value.
Two habits follow for ordinary users. First, compare what you actually receive after margins, not only the headline rate; the mid-market figure is a reference point and rarely what a customer gets. Second, be aware that a pair routed through dollars carries two margins, so asking a provider how it prices the pair is a fair question. Rates refreshed hourly on our currency grid can show you how a pair has moved against the dollar and against its neighbours.
Sources
- BIS: OTC foreign exchange turnover in April 2025
- IMF Data Brief: COFER, 2026 Q2
- Federal Reserve FEDS Notes: The International Role of the U.S. Dollar, Post-COVID Edition
- Federal Reserve History: Creation of the Bretton Woods System
- Office of the Historian: Nixon and the End of the Bretton Woods System
Checked: November 2026
