If you watch FX for any length of time, you’ll notice the same headline moving everything: a central bank and its interest rate. It’s the dominant force, so it’s worth understanding how it works.
Rates pull money across borders
Global capital is restless — it flows toward the best risk-adjusted return. When a country’s central bank sets higher interest rates, holding that currency (in bonds and deposits) pays more, so money flows in and the currency tends to strengthen. Cut rates, and the opposite pulls money out.
What really matters is the differential — the gap between two countries’ rates. A currency with a 5% rate against one with 0% has a powerful tailwind, all else equal.
Markets trade expectations, not history
Here’s the crucial subtlety: by the time a rate decision is announced, the market has usually already moved on what it expected. So a currency can fall on a rate hike if the hike was smaller than hoped — and rise on a hold if the central bank merely hints at future hikes. FX trades the surprise, and the forward guidance, more than the decision itself.
Why central banks move rates
They raise rates to cool inflation and slow an overheating economy; they cut to support growth and employment. So FX traders obsess over inflation and jobs data — because those shape what the central bank will do next.
The takeaway
Interest rates — set by central banks — are the biggest driver of currencies: higher rates (and rate differentials) draw capital and strengthen a currency. But markets price expectations, so the surprise versus what was expected is what actually moves the rate. (This is education, not investment advice.)