Currencies Explained

Every currency's value is a relative price — what one unit of money is worth in terms of another. The foreign exchange market that sets those prices is the largest and most liquid market in the world.

A currency has no price on its own

Stocks and bonds have a price in isolation — a share is worth some number of dollars. A currency cannot be priced that way, because its value only exists relative to another currency. That is why currencies always trade in pairs, like EUR/USD or USD/JPY, and the quoted number tells you how many units of the second currency it takes to buy one unit of the first. When people say "the dollar strengthened," they mean it strengthened against something specific, even if that something is left unstated.

The foreign exchange market, or FX, trades around the clock across global financial centers, handling trillions of dollars in turnover daily — far more than any stock market. Participants range from central banks managing reserves, to multinational companies hedging overseas revenue, to traders speculating on short-term moves.

Interest rates are the primary driver

The single biggest force behind currency moves is the interest rate differential between two countries. Money tends to flow toward the currency offering the higher return, all else equal, because global investors can borrow in a low-yielding currency and invest the proceeds in a higher-yielding one — a strategy known as the carry trade. When a central bank raises rates relative to its peers, its currency typically strengthens as capital flows in to capture that yield; when it cuts rates, the opposite tends to happen.

Because of this, currency markets react intensely to central bank meetings and to any economic data that might shift the expected path of rates, such as inflation and employment reports. The reaction is often less about the number itself and more about what it implies for the next rate decision.

Growth, trade, and safe-haven flows

Relative economic growth matters too: a country growing faster than its peers tends to attract investment capital, supporting its currency. Trade balances play a role as well — a country that exports far more than it imports generates steady foreign demand for its currency to settle those transactions. And during periods of global stress, certain currencies, notably the U.S. dollar, the Japanese yen, and the Swiss franc, tend to strengthen as a safe-haven reflex, regardless of that country's own economic data, simply because investors want to hold the most liquid, trusted assets available.

Why FX sets the tone for other markets

Currency moves are rarely isolated. A stronger dollar makes U.S. exports costlier abroad and can pressure the earnings of American multinationals with significant overseas revenue, while also making dollar-priced commodities more expensive for foreign buyers. That is why traders across asset classes keep half an eye on FX even if they never trade a currency pair directly — it is one of the fastest-moving signals of shifting global risk appetite and rate expectations.