US Dollar

The US dollar is the currency of the United States and, by a wide margin, the world’s most important currency. The dollar dominates international trade (most commodities are priced in dollars), serves as the reserve currency held by central banks, and is pegged or referenced by many other currencies. The dollar’s strength makes it both a financial asset and a geopolitical tool.

Historical role

After WWII, the US dollar became the international medium of exchange, displacing the British pound. Under Bretton Woods, the dollar was pegged to gold and other currencies pegged to the dollar. When Bretton Woods collapsed in 1971, the dollar began to float, but it remained dominant.

The dollar’s dominance reflects the size of the US economy (roughly 25% of world GDP), the depth and rule-of-law credibility of US financial markets, and the absence of an alternative. The euro is large but less established globally; the Japanese yen is limited by Japan’s size; the Chinese renminbi is heavily controlled and not freely convertible.

Reserve currency status

Central banks around the world hold foreign reserves: dollars, euros, gold, and other assets. The dollar is by far the largest component — typically 55–65% of identified reserves. This gives the US unique advantage: foreign demand for dollars keeps the dollar strong, allows the US to borrow in its own currency (no currency risk), and provides seigniorage (profit from printing dollars).

This reserve status is self-reinforcing: because the dollar is a reserve currency, it is liquid and trusted, which makes it more desirable as a reserve. Competing currencies must overcome this network effect.

The petrodollar

Oil and other major commodities are priced and traded in dollars. This is the petrodollar system: Saudi Arabia sells oil in dollars, earning dollars, which it holds or reinvests. This commodity pricing convention strengthens dollar demand and the dollar itself.

Some analysts argue the petrodollar status is why the US maintains military presence in the Middle East: to ensure oil continues to trade in dollars.

Dollar hegemony and its limits

The dollar’s dominance gives the US geopolitical and economic power. The US can impose sanctions by cutting access to the dollar system. It can print dollars to finance deficits (though this risks inflation). It can set global financial rules through the dollar’s influence.

But dollar hegemony is not absolute and is slowly eroding. The eurozone offers an alternative for European trade. China is pushing for renminbi internationalization. Digital currencies and decentralized finance may eventually challenge dollar dominance.

However, for the foreseeable future, no currency is close to replacing the dollar.

The dollar and the Federal Reserve

The US dollar is controlled and issued by the Federal Reserve, the US central bank. Fed policy (interest-rate changes, money-supply management) directly affects the dollar’s global value. When the Fed tightens, dollar demand rises (higher US interest rates attract capital). When the Fed eases, dollar demand falls.

For this reason, Fed policy has global spillovers. A Fed rate hike can trigger capital outflows from emerging markets, causing emerging-market currencies to weaken and local interest rates to spike.

Major pairs involving the dollar

The most heavily traded currency pairs all involve the US dollar:

• EUR/USD — most traded pair; reflects euro-dollar relative strength
• USD/JPY — dollar-yen; heavily traded; used as carry-trade funding
• GBP/USD — dollar-pound
• USD/CHF — dollar-Swiss franc
• AUD/USD — dollar-Australian dollar
• USD/CAD — dollar-Canadian dollar

These are the major pairs; all others are far less liquid.

See also