A central bank sets the price of its own currency in the most literal sense there is: the interest rate. That single number — the rate at which commercial banks borrow from and deposit with the central bank — ripples out into everything from mortgage costs to stock valuations, and in the forex market, it's one of the most reliable drivers of sustained currency moves that exists. A single earnings report or a single economic calendar release moves one pair for a session; an interest rate decision, and the expectations built around it, can drive a currency's direction for months.
How Interest Rates Move Currencies
The core mechanism is simple: money tends to flow toward wherever it earns the most. If one country's central bank pays 5.25% on deposits and another pays 0.10%, large institutional investors — banks, hedge funds, pension funds — have a direct financial incentive to hold the higher-yielding currency instead of the lower-yielding one, a strategy known as the carry trade. That demand for the higher-yielding currency, multiplied across the size of global institutional capital, is what actually moves the exchange rate, not any belief about which economy is stronger in the abstract. The wider the interest rate differential between two currencies, the stronger this pull tends to be, and the more it can offset even a fairly negative economic headline about the higher-yielding country.
The diagram above shows the mechanism in its purest form: a wide gap between two central banks' rates pulls capital toward the higher-yielding currency, appreciating it gradually over time. But it also shows the complication covered below — the actual rate decision itself can still move price in the opposite direction of what the rate differential alone would suggest.
The Major Central Banks
A handful of central banks move the forex market more than any others, simply because their currencies are the most heavily traded. The Federal Reserve (Fed) sets US dollar rates and is arguably the single most-watched institution in forex, given the dollar's role on one side of most major pairs. The European Central Bank (ECB) sets rates for the entire Eurozone, the Bank of England (BOE) for the pound, the Bank of Japan (BOJ) for the yen, and the Reserve Bank of Australia (RBA) and Bank of Canada (BOC) for two of the more commodity-sensitive major currencies. Each one holds scheduled policy meetings — roughly every six to eight weeks — where it announces its rate decision alongside a written statement and, for several of these banks, a live press conference. All three components move markets: the number itself, the wording of the statement, and anything unscripted said in the press conference about the path ahead.
"Priced In": Why a Rate Hike Can Still Send a Currency Down
This is the part that catches new traders off guard: a central bank raising rates doesn't guarantee its currency rises on the news, and can just as easily send it falling. Forex markets trade on expectations well ahead of the actual announcement — by the time a rate decision is published, most of the anticipated move has often already happened in the weeks leading up to it, a phenomenon traders call being "priced in." If the market broadly expected a 0.25% hike and gets exactly that, there's often little fresh information left to trade on, and price can drift sideways or even reverse as traders who bought the rumor sell the confirmed fact. What actually moves price on the day is usually the surprise relative to expectations — a hike that's larger than expected, a hold when a hike was expected, or forward guidance in the statement that signals more or fewer rate changes ahead than the market had priced in. Reading a rate decision means reading it against what was already expected, not against the number in isolation.
Connecting to Swap and Rollover
The interest rate differential between two currencies isn't just a slow-moving macro backdrop — it shows up directly in a trader's own account through Swap and Rollover. The swap charged or credited for holding a position overnight is, at its core, a day-by-day expression of the same rate differential covered in this lesson: holding the higher-yielding currency long against a lower-yielding one typically earns a positive swap, and holding it the other way around typically costs one. A trader who understands why a wide interest rate gap between two central banks tends to push a currency pair in a particular direction over weeks and months is also, without extra work, understanding why that same pair's swap rate leans the way it does every single night.
How to Trade Around a Rate Decision
Rate decisions bring the same practical risks as any other high-impact economic calendar event, amplified by how large and fast the reaction can be: spreads widen sharply in the minutes around the announcement, slippage on stop losses becomes far more likely, and a position sized normally for calm conditions can take a much larger loss than intended if it's still open when the number hits. Many traders choose to sit out the exact moment of the announcement rather than hold a position through it, waiting instead for the initial volatility spike to settle before reading the market's actual verdict on the decision. If you do choose to hold through a rate decision, sizing the position smaller than usual and confirming the Stop Loss distance can survive a sharp initial spike — covered in more depth in Risk Management Basics — matters more here than around almost any other scheduled event on the calendar. Rate decisions are also a useful entry point into Technical vs Fundamental Analysis: the rate decision itself is pure fundamental information, but the market's actual reaction to it is still readable on the chart with the same tools used for any other move.