What are interest rates and how do they work?

Interest rates can dictate markets, influence consumer behaviour and completely change the dynamic of an economy. Learn more about what interest rates are and how to trade them with our comprehensive guide.

What are interest rates?

Interest rates are the amount you pay to borrow money, or what you’ll receive when you save money. When you keep money in a bank account, that bank will typically pay you interest on your savings because you are in effect lending them cash.

Interest rates on loans are shown as a percentage of the total amount borrowed (the principal). For example, if the loan is £100,000 with a 5% annual interest rate (most rates are annual by default), the total owed to the lender in interest would be £5,000 in the first year.

In terms of savings, if interest rates are 5% annually and you have £10,000 in an account, you’ll have £10,500 by the end of the year – assuming interest is paid once each year.

Although commercial banks set their own rates, they aren’t the most important interest rates to traders. They are much more interested in base rates.

What are base rates?

Base rates are the amount charged by central banks to commercial banks to borrow money – and also the amount of interest paid on money held with the central bank. Base rates are seen as benchmarks, with commercial banks’ interest rates largely influenced by the base rate that’s set.

Setting the base is part of a central bank’s monetary policy. It’s the job of central banks like the Federal Reserve (Fed), European Central Bank (ECB) and People’s Bank of China (PBoC) to help support the economy they reside over by managing monetary policy and ensuring commercial banks continue to operate successfully.

Base rates tend to have a major affect on lots of markets, including forex, shares and bonds.

How do base interest rates work?

Base interest rates work by setting a rate at which a central bank is willing to lend money to other banks or pay to those holding money with them. This will should trickle down to the rates charged by commercial banks, meaning a change in the base rate will in turn cause a shift in the actual interest rates that banks are offering savers and charging lenders.
For instance, if the Bank of England (BoE) decides to raise the base rate, it would mean banks will pay more for loans when they borrow money from the BoE. Banks react to this by subsequently raising their interest rates, so they’ll also receive more money from those who they lend to.

Even the slightest change in interest rates can have a significant impact on the economy. As such, changing them is a decision that’s not taken lightly. Most central banks have selected committees comprised of several financial experts and economists who will debate monetary policy and ultimately decide whether or not to change the interest rate.

Flow diagram to show how base interest rates work

How do central banks change rates?

Each central bank amends its base rate slightly differently.

For instance, the BoE has the MPC (Monetary Policy Committee) that’s made up of nine members. Each member has an equal vote on any proposed action that’s put forward, and the outcome is relayed to the public in a press conference that’s held after the meeting on a Thursday. This happens eight times a year.

Here’s a rundown of the processes at some of the other major global central banks:


Central Bank


Number of members

Annual Meetings*

UK/GBP Bank of England BoE Monetary Policy Committee 9 8
Eurozone/EUR European Central Bank Governing Council of the ECB 25 8
US/USD Federal Reserve Federal Open Market Committee 12 8
China/CNY People’s Bank of China PBoC Monetary Policy Committee 14 12
Switzerland/CHF Swiss National Bank SNB Governing Board 3 4
Japan/JPY Bank of Japan BoJ Policy Board 9 8
Australia/AUD Reserve Bank of Australia Reserve Bank Board 9 11

*Monetary policy meetings only.

Why are interest rates changed?

Central banks change interest rates to maintain a delicate balancing act between growing the economy and keeping inflation in check.

  • They lower rates to encourage spending and try to stimulate the economy
  • They raise rates to encourage saving and try to stabilise inflation

In times of crisis, economic hardship or simply during periods where the central bank feels the economy is not quite performing as well as it should, interest rates might be lowered.
This will lower the return for those people who are saving their money in interest-paying bank accounts, which simultaneously encourages people to spend their money rather than save it. Furthermore, the increase in spending in the economy equates to a rise in demand for goods, which pushes their prices up.

On the other hand, interest rates can be raised to encourage saving. If the central banks raise interest rates, people saving money will get a greater return on their investment. Therefore, there is less incentive for people to choose to spend their money, and saving could increase.

If people are saving more money, that means less is in circulation in the economy. With less being spent, demand for goods falls and so too does the prices of these goods. This is how a reduction in interest rates can help to ease inflation – the BoE has a 2% inflation target, so anything greater than 2% could be cause for concern and action may be needed to reduce it.

Trading interest rates

We’ve established that interest rates are significant to economies, but how does this all relate to trading? Firstly, considering the correlation between economic performance and certain markets, interest rates can influence a lot of people’s trades.

Forex, stocks and indices are all heavily affected by changes in interest rates. Gold or futures markets are among others that could see volatility based on a change of interest rates. 

Plus, with City Index you can trade some of the most popular interest rates as individual markets.

Why trade interest rates?

Trading interest rates not only diversifies your portfolio and provides an opportunity to make money from rate moves, but they can also be used to hedge against the risk of a rate moving and negatively impacting your open trades.

Trading interest rate markets is the only way to directly make the most of any change in rates made by central banks. Other markets can move based on a change of rates, but other factors will also impact their prices. Whereas, when trading interest rates, you get 100% exposure to any change made by central banks.
By trading interest rates, you can hedge your risk on an interest-related asset like a bond or a loan. It’s also the opportunity to trade a less conventional market and make the most of rate movement in either direction. 

Find out more about trading interest rates with City Index.

How trading interest rates works

The price of an interest rate market aims to emulate the actual value of an interest rate. So, if rates rise then the corresponding interest rate market should also rise.

The price of an interest rate market is calculated by subtracting the actual rate from 100. So, if the ECB sets the eurozone’s interest rate to 4%, the corresponding Euribor market would be 96 (100 – 4%). 

How to trade interest rates

Follow these steps to start trading interest rates today:

  1. Open your City Index account

  2. Pick which market you want to trade

  3. Choose to go long or short

  4. Decide the amount you want to trade

  5. Set your stops and limits

  6. Open the position

Get started with a City Index account and start trading interest rate markets today. Not ready for the real thing? Test out the markets with our free demo account instead.

What moves interest rate markets?

We know the decision to change base interest rates comes from each respective central bank, but what fuels that decision and what factors do individual banks consider when setting their own rates?

Geopolitical shocks

Geopolitical shocks like international conflicts or pandemics can have a huge impact on an economy. Shocks can devastate economies as these often come suddenly and don’t allow any time to prepare for the impact. What’s more, as we saw with the Covid-19 pandemic, the effects are typically damaging and long-lasting. As a result, central banks use interest rates to attempt to limit the impact.

Since the turn of this decade, several central banks have chosen to lower interest rates and set them below 0% so that they’re negative. It’s seen as a risky form of action and as such, negative rates have been the focal point of much deliberation among many of the major central banks.


A main target for central banks to focus on is employment. Low unemployment benefits an economy as it means more people are in work and earning disposable income that could then be circulated back into the economy.

When rates are low, it’s cheaper for companies to take out loans and expand their business, which in turn creates more jobs. If a central bank wants to help lower unemployment, it may lower interest rates. It’s therefore important to look at employment levels when trading interest rates, as the two are closely linked with one another.


Inflation in an economy is a major factor in dictating interest rates. When inflation is high, central banks will set rates high to try to encourage saving and stem the rise in prices of goods and services. Equally, banks will raise their interest rates to compensate for the reduction in purchasing power for the money they’re owed.

Interest rates FAQ

Can you make money trading interest rates?

Yes, you can make money by trading interest rates on all the markets we offer. However, like all trades, there is risk involved. You aren’t guaranteed to make a profit and could even incur substantial losses if the market goes against you.
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Who sets interest rates?

The base interest rate is set by central banks, and is the rate that it pays to commercial banks who hold money with them. For instance, a commercial bank in the UK might hold a significant amount with the BoE, therefore, the interest rate that’s set by the BoE will directly determine how much the commercial bank will receive back from its investment.

A commercial bank will use the base interest rate as a benchmark to set their rates, although ultimately, they can choose to set their own rates at whatever level they like.

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How much are interest rates changed by?

If we use the BoE as an example, interest rates are often changed by measurements of 0.25%. For instance, if rates are at 1%, a typical move would be up to 1.25% or down to 0.75%. However, there are no exact restrictions on how much interest rates can be changed. In times of crisis, such as the 2008 global recession, the BoE has been known to move rates more drastically, with a change of 1.5% coming in December 2008.
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How often are interest rates changed?

Interest rates are reviewed frequently, but the amount they actually change depends on the given economy’s monetary policy, the state of that economy and the intentions of the governing central bank. Many central banks have interest rate meetings eight times a year, but rate changes come far less frequently. If interest rates were changed each time, the impact of the previous change might not have had time to manifest.
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