Why the Dollar Rules the World: How One Nation's Currency Runs the Global Economy

A farmer in Sri Lanka, an oil trader in Dubai, and a central banker in Beijing have something surprising in common: they all, in one way or another, depend on the US dollar. It is the currency the world trades in, saves in, and prices its oil in — even in transactions that have nothing to do with the United States. How did one country's money come to run the entire global economy, what extraordinary advantages does it give America, and is its reign finally coming to an end?

Here is a fact that ought to seem strange but is so familiar we rarely notice it: when a company in Japan buys oil from Saudi Arabia, or a business in Brazil trades with one in India, the deal is very often done in US dollars — a currency belonging to neither party. The dollar is not merely America's money; it is the world's money, the common financial language of the entire planet. It dominates global trade, international lending, and the savings of nations. By some measures the dollar is involved in the vast majority — around nine in ten — of all foreign-exchange transactions on Earth, and it makes up well over half of the reserves that the world's central banks hold in their vaults.

This is one of the most consequential facts about the modern world, and one of the least understood. Why should one nation's currency hold such power? The answer is a story of war, trust, oil, and the strange self-reinforcing logic of money — and it has enormous stakes, both for the United States and for everyone else.

How the dollar took the throne

The dollar was not always king. For much of the nineteenth and early twentieth centuries, the British pound sterling was the world's dominant currency, reflecting Britain's vast empire and economic might. The dollar's rise to supremacy was sealed by the two World Wars and their aftermath.

The pivotal moment came in 1944, as the Second World War drew toward its close. Delegates from the Allied nations gathered at a conference in Bretton Woods, in the United States, to design a new international financial order for the postwar world. The system they created placed the US dollar at its centre: other countries would fix their currencies to the dollar, and the dollar itself would be tied to gold, exchangeable at a fixed rate. This arrangement made the dollar the anchor of the entire global monetary system. It was a natural choice — by the war's end, the United States was overwhelmingly the world's largest economy and industrial power, had emerged from the war immensely strong while its rivals lay devastated, and held the lion's share of the world's gold reserves. The dollar became the currency everyone else built their money around.

That gold-backed system eventually broke down. By the early 1970s, the United States could no longer maintain the promise to exchange dollars for gold at a fixed price, and the link to gold was severed — an event known as the "Nixon Shock." Many expected the dollar's dominance to fade along with its golden backing. Instead, something remarkable happened: the dollar's reign not only survived but endured, now backed not by gold but by the sheer size and strength of the American economy, the depth and openness of its financial markets, and the trust of the rest of the world. And a new pillar soon emerged to reinforce it.

Oil, trust, and the network effect

In the 1970s, the dollar acquired a powerful new foundation: oil. Following the oil shocks of that decade, the United States reached understandings with major oil-producing nations, above all Saudi Arabia, under which oil would continue to be priced and sold in dollars. This created what became known as the "petrodollar" system, and its logic was quietly enormous. Because virtually every country needs to buy oil, and oil is priced in dollars, virtually every country needs dollars. The world's most essential commodity became a giant engine of demand for the American currency.

But the deepest reason for the dollar's staying power is something more abstract: trust and what economists call the network effect. Countries and businesses hold and use dollars because they trust the dollar to hold its value and to be accepted anywhere — and that trust rests on the stability of American institutions, the rule of law, and financial markets so large and liquid that you can buy or sell dollar assets, in enormous quantities, at any time. The US government bond market, where dollars are parked in the form of Treasury securities, is the deepest and most trusted pool of safe assets in the world.

And then the network effect locks it all in place, in a beautifully self-reinforcing loop. Because everyone else uses dollars, any new participant in global trade must use dollars too. Oil is priced in dollars, international loans are made in dollars, most trade is settled in dollars — so every actor in the system needs dollars, which makes the dollar even more entrenched, which forces the next actor to use it as well. It is like a global language: English dominates international business not because it is the "best" language but because so many people already speak it that everyone else must learn it too. The dollar dominates for the same reason. Rivals like the euro exist and are used, but no other currency comes close, held back by smaller or more fragmented financial markets and less complete trust. The dollar's dominance, once established, feeds on itself.

The "exorbitant privilege"

Why does all this matter so much? Because holding the world's reserve currency grants the United States a set of extraordinary advantages — benefits so large that a French official once memorably called them America's "exorbitant privilege."

The most important is the ability to borrow cheaply and almost limitlessly in its own currency. Because the whole world wants to hold dollars and dollar assets, there is constant, enormous demand for US government debt. That demand pushes down the interest rate the US government has to pay to borrow, saving it a fortune and allowing it to run large deficits that would cripple another country. A nation whose debts are denominated in a currency it alone can print is in a uniquely comfortable position: it need never fear being unable to repay, because it controls the printing press for the very money it owes. Beyond cheaper borrowing, the dollar's status attracts investment into American markets, lets American businesses and consumers trade and buy imports without currency risk, and earns the US a steady income simply from the fact that dollars circulate around the world.

There is also a harder-edged power: because so much of global finance flows through the dollar system, the United States can use access to that system as a weapon, imposing financial sanctions that can effectively cut a country, company, or individual off from the global economy. This ability to "weaponise" the dollar is one of the most potent tools in modern geopolitics — and, as we will see, one of the reasons some countries are now trying to reduce their dependence on it.

The hidden cost — and the debate about the future

The dollar's dominance is not pure benefit, even for America, and here lies a genuine paradox. To supply the world with all the dollars it wants to hold, the United States must effectively send those dollars out into the world — which it does, in large part, by running persistent trade deficits, buying more from other countries than it sells to them. In other words, the dollar is dominant partly because there is so much American debt and so many American dollars for the world to absorb. Some economists argue this "exorbitant privilege" comes with an "exorbitant duty": the strong demand for dollars keeps the currency strong, which makes American exports more expensive and can hollow out domestic manufacturing. The privilege of issuing the world's money, in this view, quietly contributes to some of America's economic imbalances.

All of which raises the question everyone eventually asks: is the dollar's reign coming to an end? There is much talk of "de-dollarisation" — of countries seeking to trade in their own currencies, of rivals building alternative payment systems, of central banks quietly diversifying their reserves, partly in response to the weaponisation of the dollar through sanctions. These trends are real, and the dollar's share of global reserves has drifted down somewhat from its peak. It would be foolish to assume any arrangement lasts forever; the pound, too, once seemed unassailable.

But the honest assessment is that the dollar's dominance, while not eternal, is extraordinarily durable, precisely because of that self-reinforcing network effect. Dethroning the dollar would require not just dissatisfaction with it, but a genuinely superior alternative — another currency backed by an economy as large, markets as deep and open, and institutions as trusted as America's — and no such rival currently exists. The euro is fragmented; other contenders lack the open financial markets or the trust required. For all the talk of its decline, the dollar remains, for now, firmly on its throne, held there less by American power alone than by the simple fact that the whole world is already built around it.

What it means for a country like Sri Lanka

For a small, import-dependent country, the dollar's dominance is not a distant abstraction — it is a fact of daily economic life, and sometimes a matter of survival. Nations like Sri Lanka must earn or borrow dollars to pay for the essentials they import: fuel, medicine, machinery, and much of their food. Their exporters are paid in dollars, their tourists bring in dollars, and their overseas workers send home dollars; and it is with those dollars that the country pays its foreign bills. When that flow of dollars dries up, the consequences can be catastrophic.

Sri Lanka lived through exactly such a catastrophe in 2022, when the country effectively ran out of foreign currency. Without enough dollars to pay for imports, the island suffered crippling shortages of fuel, cooking gas, and medicine; power cuts stretched for hours; and the government was ultimately forced to default on its foreign debt — debt that, like that of most developing nations, was owed largely in dollars. The crisis was a brutal lesson in the hard edge of a dollar-centric world: a country can be brought to its knees not because it has run out of its own money, which it can always print, but because it has run out of the world's money, which it cannot. When your debts and your import bills are denominated in a currency you do not control, the dollar's dominance stops being an American privilege and becomes your vulnerability.

This is the other side of the "exorbitant privilege." The same system that lets the United States borrow cheaply and print the money it owes leaves developing countries exposed to forces they cannot command — to the decisions of the US Federal Reserve, to swings in the dollar's value, and to the terrifying possibility of a dollar shortage. It is part of why so many emerging economies are watching de-dollarisation efforts with interest, and why the question of who controls the world's money is far from academic for the billions of people who live in its shadow.

The invisible architecture

Most of us never think about which currency underpins the global economy, any more than we think about the foundations of the building we live in. But the dominance of the dollar is one of the invisible structures that shapes the modern world — determining how nations trade, how crises spread, whose economy sets the weather for everyone else, and even how much a Sri Lankan importer pays for goods from a country that has nothing to do with the United States.

It is a striking illustration of how power works in the modern age: not only through armies and territory, but through the quiet, compounding advantage of issuing the money that everyone else has agreed to use. The dollar rules the world not because anyone recently decided it should, but because of a chain of history — a war won, a system built, an oil bargain struck, a network entrenched — and because, once a currency becomes the world's money, the whole world has a stake in keeping it there. Understanding that is understanding one of the deepest and least visible sources of power on the planet.

Sources and further reading

• IMF, World Economic Forum, and US Federal Reserve (St. Louis and Philadelphia Fed) data on the dollar's share of global reserves (~58%) and its involvement in around 89% of foreign-exchange transactions (Bank for International Settlements, 2025).
• Histories of the dollar's rise: the displacement of the British pound, the 1944 Bretton Woods conference, the dollar-gold anchor, and the 1971 "Nixon Shock" ending gold convertibility.
• Accounts of the petrodollar system (dollar-priced oil and Gulf-state investment in US debt) and the "network effect" reinforcing dollar dominance.
• Analyses of the "exorbitant privilege" (cheaper US borrowing, seigniorage, sanctions power) and the "exorbitant duty"/reserve-currency link to persistent US trade deficits (Atlantic Council, Bipartisan Policy Center, and related work).
• Reporting on de-dollarisation trends, the weaponisation of the dollar through sanctions, and assessments of why the euro and other currencies have not displaced it.