Of all the factors that influence currency markets, interest rates are among the most closely watched, and for good reason. Central bank interest rate decisions are one of the most consistent drivers of exchange rate movements, and understanding this relationship helps explain why currency markets react so strongly to central bank announcements.
The Basic Relationship
Generally speaking, higher interest rates tend to support a stronger currency, while lower interest rates tend to put downward pressure on it. This happens because interest rates affect the relative appeal of holding a particular currency.
Why Higher Interest Rates Attract Investment
When a country raises interest rates, it generally becomes more attractive for investors to hold assets denominated in that currency, such as government bonds, because they offer a better return. This increased demand for the currency (in order to purchase those assets) tends to push its value higher.
Why Lower Interest Rates Can Weaken a Currency
Conversely, when interest rates fall, the returns available on assets in that currency become less competitive compared to other countries. This can reduce demand for the currency, as investors look elsewhere for better returns, putting downward pressure on its value.
It’s Not Just the Rate – It’s the Relative Difference
What matters most isn’t necessarily a country’s interest rate in isolation, but how it compares to interest rates elsewhere, particularly in major economies like the US. This is often referred to as the “interest rate differential.”
For example, if Australia’s interest rates rise while US rates stay the same, the AUD may strengthen against the USD, as Australian assets become relatively more attractive. If the gap narrows or reverses, the opposite effect can occur.
Expectations Matter as Much as Actual Decisions
Currency markets don’t just react to interest rate decisions themselves, they often react to expectations about future decisions. If the market expects a central bank to raise rates, that expectation can start influencing the currency’s value even before the actual announcement. This is why central bank commentary and economic data (which hint at future rate decisions) can move currency markets significantly.
Central Bank Policy and Currency Markets
Central banks, such as the Reserve Bank of Australia or the US Federal Reserve, set interest rates primarily to manage inflation and support economic stability, not to directly control currency values. However, because of the strong link between interest rates and currency demand, these decisions have a significant flow on effect on exchange rates, even though that’s not their primary purpose.
A Practical Example
Imagine the RBA raises interest rates while other major central banks hold steady. All else being equal, this could make the Australian dollar more attractive to international investors seeking better returns, potentially strengthening the AUD against other currencies.
Now imagine the reverse, the RBA cuts rates while other central banks hold or raise theirs. This could make the AUD relatively less attractive, potentially leading to a weaker exchange rate.
Why This Matters for Businesses
For businesses with foreign currency exposure, interest rate decisions, both domestic and international, are one of the key events worth watching, as they can directly influence the exchange rates relevant to upcoming payments or receivables. A central bank meeting scheduled before an important transaction date, for example, is worth factoring into planning.
Final Thoughts
Interest rates are one of the clearest, most consistently influential drivers of currency values, but they rarely act alone. Economic data, geopolitical events, and market sentiment all interact with interest rate expectations to shape currency movements. Understanding this relationship doesn’t make exchange rates predictable, but it does help explain why they move the way they do.
GenCap helps businesses stay informed on the market factors that influence currency movements, and provides tools to manage the impact on international payments.
