Carry Trade
The logic is straightforward: if one country's benchmark interest rate is, say, 0.5% and another's is 6%, borrowing in the cheap currency and parking money in the expensive one earns roughly the gap — the interest-rate differential — as long as the exchange rate stays stable. This flow of capital toward higher-yielding currencies is a significant driver of what moves exchange rates over medium timeframes.
Historically, the Japanese yen has often been the "funding currency" in carry trades because Japan maintained very low rates for extended periods. Traders would borrow yen, convert to a higher-yielding currency like the Australian dollar or a emerging-market currency, and earn the spread. You can follow benchmark rates across economies on the indicators and countries pages.
The risk is the unwind. If the high-yield currency suddenly weakens — or the funding currency strengthens sharply — the exchange-rate loss can wipe out months of interest income in days. During risk-off episodes, carry trades often unwind rapidly and en masse, amplifying currency moves. The 2008 financial crisis produced one of the most dramatic carry-trade unwinds in modern history, with the yen surging as traders rushed to close positions.
Economists read carry-trade positioning as a gauge of global risk appetite. Heavy carry-trade activity signals confidence; a sudden reversal signals fear. See the carry trade basics guide for a fuller walkthrough of the mechanics.