How Interest Rates Move Markets

Interest rates influence every major financial market.

They affect how much households pay to borrow, how easily businesses can invest, what investors can earn from bonds, and how attractive one country’s currency appears relative to another.

Yet for something so powerful, the mechanics are surprisingly simple. This guide breaks down what interest rates are, how they're set, and how they ripple through every major asset class traders watch.

What are Interest Rates?

An interest rate is the price of money. Borrow, and the rate is the cost of doing so. Save or lend, and it's the return you earn instead. That rate is expressed as a percentage of the amount borrowed (the principal) over a set period of time.

For example, if you borrow $1,000 at an annual interest rate of 5%, the interest would be $50 over one year, before accounting for fees or compounding. The principal here is the original $1,000.

The same idea works in reverse for savers. When you deposit money with a bank, the bank may pay you interest because it can use those funds to provide loans and conduct other financial activities.

How Are Interest Rates Determined?     

So who sets the price of money? Commercial banks set their own rates, but they all take their cue from the central bank. In the US, that's the Federal Reserve, in the eurozone, it’s the ECB, and in the UK, it’s the Bank of England.

A central bank acts as a bank for commercial banks. It conducts monetary policy mainly by setting a short-term policy rate that influences the interest rate banks charge each other.

That cost passes through to mortgages, loans, and credit cards, shaping how much people spend, businesses invest, and companies hire, all the way to prices at the grocery store.

The goal is generally price stability and, depending on the mandate, healthy employment and sustainable growth. Cutting rates makes money cheaper, encouraging borrowing, investment, and spending. Raising rates makes borrowing more expensive, cooling the economy and easing price pressure.

Central banks have the strongest influence over short-term interest rates, which apply to borrowing and lending over relatively brief periods, usually from overnight to around one year. They mainly guide these rates through their policy rate.

They may also use open-market operations to buy or sell short-term securities, lending facilities to provide temporary funding to banks, and reserve requirements to influence how much banks can lend. Together, these tools affect liquidity, bank funding costs, credit availability, and short-term borrowing conditions.

Central banks can also influence long-term interest rates, which apply to borrowing over several years, including government bonds, corporate debt, and mortgages. However, these rates are also shaped by expectations for future policy, inflation, and economic growth, as well as supply and demand in the bond market.

During periods of uncertainty, investors may move into government bonds for safety, pushing bond prices higher and long-term yields lower.

Interest Rates and Stocks

Stocks and interest rates usually move in the opposite direction, especially when higher rates threaten growth, spending, or company profits.

If a central bank raises interest rates, borrowing becomes more expensive for consumers, which can reduce spending and demand for loans.

Companies can feel the pain too, especially heavily indebted ones. Higher borrowing costs reduce company profits, which may put downward pressure on share prices. Rising rates can also make bonds more attractive relative to stocks, pulling money out of equities altogether.

Cut rates, and the sentiment flips. Lower rates can make new borrowing and refinancing cheaper, support investment, and reduce the discount rate applied to future earnings. These effects may support stocks, although cuts can also signal that the economy is weakening.

Interest Rates and Commodities

Higher interest rates can weigh on commodities too, but the impact differs from asset to asset. 

Gold is highly sensitive to interest rates, for the simple reason that it pays nothing. No interest, no dividend, no income.  

When rates rise, bonds and savings accounts start offering better returns, so every ounce of gold a trader holds is money that could be earning interest elsewhere. Economists call this the opportunity cost of holding gold, and when it rises, demand for the metal often falls. 

What matters most here is the real yield, which is the return on bonds after subtracting inflation. If bonds pay 5% but inflation runs at 4%, the real yield is just 1%, and gold gives up little by paying nothing.  

When real yields are high, gold struggles. When they fall or turn negative, gold tends to shine. 

That said, the relationship isn't a law. Gold can rise even while yields climb. During strong inflation, geopolitical turmoil, or financial instability, its role as a safe haven can outweigh the math. 

Oil plays by different rules. Rates influence oil mainly through demand. Higher rates slow economic activity, and a slower economy burns less fuel. But oil has powerful forces on the supply side too, like production levels, inventories, geopolitics, and the decisions of OPEC.

Lower rates tend to support commodities broadly by encouraging spending, investment, and risk-taking. They can also lift inflation expectations, increasing demand for assets seen as inflation hedges, such as gold, copper, and silver.

Interest Rates and Currencies

Interest rates are a direct lever on currency values and exchange rates.

When a country's central bank raises interest rates, the national currency usually appreciates in value.     

On the flip side, the currency generally loses value when interest rates are lowered because foreign investors often respond by moving their money to other countries in search of higher returns.    

But as usual, inflation can sometimes complicate the picture. A country can raise rates and still watch its currency weaken if inflation is eating away at purchasing power faster than the higher yield can compensate.

The lesson here is that rates matter, but never in isolation. Read them alongside inflation and the rest of the economic picture.

Understanding Interest Rate Differentials

An interest rate differential is the gap between two countries' interest rates, and that gap is one of the biggest drivers of currency values.

Usually, the country with the higher rate tends to see its currency appreciate against the one with the lower rate. Traders keep a close eye on central bank meetings and economic data, trying to get ahead of where that gap is heading next.

Take the Fed and the ECB. If the Fed raises rates while the ECB cuts, traders will often sell the euro and buy the dollar, shorting EUR/USD and betting on dollar strength from the widening rate gap.

Government bond yield differentials can also impact currencies because they change the relative return investors can earn by holding one currency against another.

Let's look at an example using 2-year government bond yields:

• US 2-year yield: 4.50%
• UK 2-year yield: 3.80%
• US-UK differential: +70 basis points

If bond yields in the US are higher than UK yields and are rising at a faster pace, the US dollar could become more attractive than the British pound. That positive spread, or interest rate differential, supports the dollar because investors are paid more to hold USD assets than GBP assets.

But here’s the catch. A widening differential doesn't automatically strengthen a currency. It depends on why yields are rising.

If US yields rise because markets expect stronger economic growth or a more hawkish Federal Reserve, the dollar may strengthen as investors anticipate higher returns on US assets.

However, rising yields do not always support a currency. If UK yields rise because of persistent inflation, debt concerns, or political risk, the pound may weaken despite the higher yields. In this case, investors may demand greater returns as compensation for increased risk.

The yields move higher in both cases, but one rise reflects stronger economic expectations, while the other reflects greater uncertainty.

In FX markets, traders often watch two-year yield differentials more closely than ten-year spreads because they tend to reflect expectations for central bank policy. Currencies can move sharply when those expectations change.

The Carry Trade: Borrow Low, Invest High

The carry trade is one of the oldest tricks in the FX playbook. The idea is simple. Borrow in a currency with a low interest rate, then invest the funds in a currency yielding a higher interest rate, and seek to profit from the interest rate differential.

But it's not free money. The trade lives and dies on exchange rates, because the loan must eventually be repaid in yen. If the yen strengthens against the Australian dollar while the position is open, buying it back costs more, and those currency losses can wipe out the interest earned, or worse.

Rate spread and FX risk move together in this trade, and ignoring the risk is how carry trades end up in disaster.

The Bottom Line

Interest rates sit at the center of financial markets. They set the cost of borrowing, shape consumer spending, and drive the pace of economic activity, and every asset class feels it.

Higher relative returns can draw in foreign capital and support a currency, lower rates tend to push that capital and the currency's value the other way.

For traders and investors, rates aren't background noise. They're a signal worth tracking closely, because reading them right is half the game.