How does the stock market work?

Despite all the jargon and confusing displays with thousands of numbers, investing is actually pretty simple at its core. Don’t believe us? Allow us to explain the stock market to you.

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The stock market might seem like the reserve of high-flying city bankers and the more mathematically-minded among us. But the truth is that the world of investment is a lot more accessible than you might think – albeit with some risks.

To help you get to grips with it at all, we’ve put together a one-stop shop for learning all the basics of the stock market. From what the market actually is, to how to buy stocks and shares, and where the experts recommend you invest, plus everything in between, we’ve got you covered.

This guide is intended for educational purposes only and should not be considered as investment or financial advice.

What are stocks and shares?

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There are theoretically slight differences between ‘stocks’ and ‘shares’, but really they are two words for the same thing: owning a slice of a company.

Typically a single stock or share will only be worth a very, very small percentage of a business (we’re talking much smaller than 1%), but if you own even one, you’ll own part of that company. You can also invest in funds and indexes, which we explain in more detail later.

You can buy shares in most of the world’s biggest businesses, including Apple, Amazon and some British companies like Vodafone and Tesco. In fact, the stock market is pretty much exclusively populated by big businesses, as that’s one of the requirements that a company must meet before entering the market (known as ‘going public’ or ‘floating’).

Other criteria a company needs to go public include having:

  • A predictable and consistent revenue stream
  • The potential to grow further in the future
  • A long-term business plan.

But why would a company go public in the first place? Well, while it does invite some extra pressures like having to answer to shareholders and being subject to a constant expectation of short-term growth, there is one major benefit: money.

Assuming investors actually buy the stocks, going public gives a company a huge injection of cash which can then be used to fund future growth.

What is the stock market?

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Essentially the stock market is just like any other market, in that it’s a place for trading assets of value. In this case, company stocks.

While we’d never recommend that you get involved in the stock market without doing some research first, you certainly don’t need to understand every little thing about the way it works to start investing.

But don’t just take it from us – take it from the most successful investor of all time, Warren Buffett:

If calculus or algebra were required to be a great investor, I’d have to go back to delivering newspapers.

Warren Buffett

Although people often talk about ‘the’ stock market, the reality is that there are lots of them. The New York Stock Exchange (commonly referred to as simply ‘Wall Street’) is the biggest of the bunch, but there are dozens of others around the world, including the London Stock Exchange.

Companies are usually listed on the stock markets of the countries in which they’re based, but in today’s digital world this doesn’t really matter as much as it used to.

Thanks to online trading platforms, someone in England can now buy shares listed on the New York Stock Exchange just as easily as they could purchase shares on the London equivalent.

What are stock market indices?

Stock market indices (also known as ‘indexes’) measure the performance of a particular group of companies.

The companies within a single stock market index will always have something in common, whether it’s because they’re all in the same country or continent, because they’re in the same industry, or because they’re all considered to be highly reputable and reliable investments (also known as ‘blue chip’ companies).

You may have heard of the FTSE 100, for example – that’s a UK stock market index containing the current 100 most valuable companies listed on the London Stock Exchange.

How are share prices set?

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When a company goes public, the first batch of shares released to the market is known as an Initial Public Offering (IPO).

The price at which these shares are set is determined by a consultation process between the company itself, an investment bank and a group of initial investors. Various factors are used to help decide a price, but arguably the most important is the value of the company at that time.

Once shares have been released to the market, however, the price is effectively set by an auction process.

To explain, we’ll use an example: let’s say Investor A bought stocks in a company for £1 a share and wants to sell, but Investor B thinks they’re only worth 90p a share.

The two traders must come to an agreement in order to make the sale, so if Investor B thinks the value may rise in the future, they may agree to buy the shares for slightly more than their first offer.

Similarly, if Investor A thinks the value is set to decrease soon or they’re keen to make the sale for other reasons, they may agree to sell their shares for slightly less than £1 a pop.

As there are millions of investors and traders operating on the stock market, each company’s shares will likely be traded thousands of times every day, often by people who have differing opinions on their value.

These individual opinions won’t be massively different (you’d rarely find one trader saying a share is worth £1 while another says it’s worth 5p), but each trade will affect the price. In fact, at any given moment, the value of a stock is quite literally the last price at which it was sold during market hours.

What makes stocks go up and down?

These are some other factors that may cause a stock’s value to go up or down:

How to buy shares

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And it’s not just companies you can invest in – you can also trade in commodities (like gold or oil) and currencies (including cryptocurrencies like Bitcoin). However, it’s worth noting that these types of investments are much riskier than trading shares in public companies.

The other advantage of investment platforms is they remove the barriers to entry historically associated with buying shares, so they are particularly popular with those starting out who want to learn about the stock market by trading. eToro has a virtual stock market which is great for practising without risk (see our guide to stock market investing for more).

Before you open a real trading account with any platform or broker, make sure you understand the fees involved in the service. Charges vary from platform to platform, so do your research before signing up (more on this later).

Should you buy shares or invest in funds?

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As a trader, you have the option to either directly buy shares in companies, or invest in funds (groups of similar companies).

Funds will usually focus on a particular region or theme; ‘European businesses’ or ‘green-energy companies’ are the kinds of things you might see a fund based upon.

The decisions on how the fund’s money is spent are made by a fund manager. They are so-called ‘experts’ in their field, and it’s their job to ensure the fund increases in value as best they can.

If one or more of the companies in the fund performs poorly, it’s not a disaster. Your money has been invested across multiple businesses, so a limited amount of your capital is at risk if that one company fails.

And that’s the main benefit of investing in funds: the risks are typically much lower as funds are diversified.

The problem with most funds is that they have fund managers, which are both expensive and human. However much experience they may have, and whatever promises they try to make, they cannot predict the future.

Index funds address both of these issues. They simply track stock market indices (like the FTSE 100) which naturally focus on the healthiest companies at any given time. With no fund managers’ salaries to pay, the product fees are significantly cheaper – and over the long term, they’ve been proven to outperform any managed fund.

How investing in funds reduces risks and returns

To exemplify, imagine you have £100. You’re not sure whether to invest in a company (let’s call it DabCorp) or into a fund that invests in 100 companies – one of which is DabCorp. For the sake of argument, let’s say that this fund invests that £100 equally across every company – so that’s £1 per company.

Now, let’s imagine DabCorp goes bust on day one. By investing via a fund, you’re only losing £1. But if you’d invested all £100 in DabCorp, you’d suddenly lose everything.

While the prospect of doubling your money sounds great, you should pay equal attention to the risk of losing everything. Even the most experienced investors use funds, which tells you everything you need to know about the importance of mediating risk.

How much money do you need to buy shares?

There’s a misconception that investing in the stock market is only for the wealthy.

But, while it’s certainly sensible to only invest as much as you’re prepared to lose (and being able to make this choice is, of course, a luxury that not everyone has), it’s also true that you don’t need to have thousands of pounds lying around to get involved in stocks.

An individual share in a company can be worth pennies so, in theory, almost anyone could own at least one stock. However, even if that share increased in value 100 times over, you’d still only have a few quid.

As such, you’d probably need to invest at least £100 in the market to make it worth your while. But we’ll say it again: you shouldn’t invest more than you’re prepared to lose.

When should you buy and sell shares?

Once again we return to the concept of risk.

When it comes to investing, you can either take a short- or long-term approach, and at the more extreme end of the short-term scale is what’s known as ‘day trading’. This quite literally involves buying and selling shares within a single day of trading and, as you might expect, it’s a very risky approach that often results in making a loss.

Your chances of making a profit on your investment (or, more importantly, the chances of not losing all your money) are a lot better if you stick with it for a longer period of time.

If you’re confident that the company you’ve invested in has a good long-term future, it doesn’t matter if it rises or falls in the short term – as long as the value of your stock increases in value over several months or years, you’ll be golden.

This sentiment is one supported by Warren Buffett, who once famously said:

Someone is sitting in the shade today because someone planted a tree a long time ago.

Warren Buffett

So, we know that waiting it out is often wisest when you’re thinking of selling stocks. But what about buying? When should you take the plunge?

Nobody can predict the future, so it can be tricky to determine exactly when a stock has bottomed out, or whether it’ll continue to drop for some time.

But, in the event of a market-wide slump, like the 2008 financial crisis or the COVID crash of 2020, you can be relatively confident that any shares you buy will be worth more than you buy them for, even if they continue to lose value after the purchase.

Chart credit: Google

The image above shows the value of the FTSE 100 over time. As you can see, even after the devastating financial crash of 2008 (marked with a 1 on the chart) and the coronavirus crash of 2020 (marked with a 2), the overall trend is still one of growth.

Similarly, if you already own shares and the market suddenly tanks, selling might not be the best option. As the chart shows, historically the market will always recover in the long-term, going on to exceed previous peaks.

Or, as Warren Buffett puts it:

We simply attempt to be fearful when others are greedy, and to be greedy only when others are fearful.

Warren Buffett

How can you make money from shares?

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In reality, it’s not quite as straightforward as that. Pinpointing the very best times to buy and sell is a skill that takes time to acquire, and you shouldn’t expect to make a fortune on the markets (at least not straight away, anyway).

That’s because dividends are paid equitably – in other words, the more shares you have, the more dividends you receive. And so it follows that, if you invest those dividends as more stock, the next time dividends are paid, you’ll receive an even greater proportion.

This phenomenon is known as compounding, and is similar to how your savings can grow exponentially with interest (something you can learn more about here).

But what it shows is how reinvesting your dividends can, over time, lead a substantial growth in the value of your portfolio, without you having to invest a single extra penny.

If you’re investing in funds, dividends will be automatically reinvested on your behalf.

Why should you invest in the stock market?

These are the main benefits of investing in stocks and shares:

Long term, investing can make more money than saving

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If you’re fortunate enough to have any spare cash lying around, you should usually look to put it into a savings account or an ISA. But that’s only half the story.

These accounts are good for increasing the value of your savings in the short or medium term but, over longer periods, investing in the stock market usually provides greater returns. This has especially been the case since the financial crash of 2008, since which, interest rates have been consistently low.

Although there are ways to be relatively sure of a return over the long term…

Over long periods, indices always go up

As we explained earlier, over the course of several years, stock market indexes always increase in value.

And this isn’t just true of indices tracking the biggest companies in a given region (like the FTSE 100) – regardless of what the index covers, these are usually a pretty sure bet for making a return on your investment.

Stocks and shares ISAs let you make tax-free gains

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If you happen to make a substantial profit on the stock market, you’ll be liable to pay Capital Gains Tax (CGT).

The earlier you start investing, the better

As you might have picked up by now, the key to increasing your chances of success in the stock market is to play the long game. Naturally, then, it only makes sense that the earlier you start investing, the more your money could grow.

There are a few reasons for this. Firstly, given that stock market indices tend to increase in value over long periods of time, it follows that investing earlier should mean you make a larger profit by the time you want to cash out.

Secondly, thanks to the magic of compounding (explained above), the more often you’ve reinvested your dividends as extra stock, the more dividends you’ll receive, and the greater the value of your investments will be.

Finally, there’s something to be said for our old friend experience. You don’t need to be an expert to get involved in investing, but there’s no denying that being able to learn from your mistakes and see how the market operates first-hand is beneficial.

You probably already have investments

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If you’ve got this far and don’t think the stock market is quite your thing, we’ve got news for you: you may well already have skin in the game.

As it can be lucrative in the long term, most private pension funds invest in the markets. So, if you have a job and a pension, the chances are that you already have money in the stock market – at least indirectly, anyway.

For that reason alone, isn’t it worth clueing yourself up on the stock markets and knowing what your retirement fund is up to?

What are the risks of investing in the stock market?

These are the main dangers of investing in the stock market:

The value of your investments can go down

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We’ve mentioned it a few times already, but it bears repeating: when you invest in stocks and shares, there’s a chance that their value will decrease and you’ll lose money.

How much you lose will depend on how much you’ve invested and how poorly the company (or companies) performs. But, in an extreme case, you could stand to lose everything that you’ve invested.

This is in stark contrast to an ISA or regular savings account. Unless you go for an account with a negative interest rate (almost unheard of in the UK), pretty much the only way you’ll lose any money with one of these is if the bank goes bust, in which case you could lose anything over the protected amount (usually £85,000).

Investment decisions based on emotion

With share prices going up and down all the time, it’s easy to get sucked into the drama of the stock market.

History may end up vindicating both decisions, but they could just as easily (and, arguably, more likely) look very foolish in time. That’s because both are examples of decisions being lead by emotions, and not by reason – something that most people who have been successful in the stock market would advise against.

Chasing losses

Making decisions based on emotion really is one of the biggest dangers of the stock market, and it could lead to you chasing losses.

Put simply, chasing losses is when you invest extra money in an attempt to make up for a drop in the value of some other shares that you own. However, doing this misses a very crucial point: you haven’t lost a penny unless you actually decide to sell at a loss.

Remember that, as the FTSE 100 graph above shows, even a dramatic fall in share price doesn’t necessarily mean it won’t recover and go on to exceed the price you first bought it at.

As Warren Buffett famously said, patience is the key:

Our favourite holding period is forever.

Warren Buffett

Some markets are very risky

All investments entail at least some risk, but some involve a lot more than others.

Index or diverse funds are typically seen as the safest way to invest, while forex trading is undoubtedly one of the riskiest. Forex is short for ‘foreign exchange’, and is the name given to the markets where investors trade currencies.

Chances are you’ll have seen loads of TikToks and ads online promoting forex trading as a way to make money quickly, but the truth is that very few people involved in this corner of the market make a profit.

As the financial journalist, Andrew Hallam, explains in this guide to investing your money, for every dollar made in a forex trade, a dollar is lost elsewhere. Therefore, the only guaranteed winner is the investment bank making money on commission – the real reason forex trading is pushed so hard to people with little or no knowledge of the stock market.

Hidden fees

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There are lots of different fees that you could be charged depending on the type of investment and how it’s managed. Some common ones include a platform fee, a fund manager charge and a fee every time you buy or sell shares.

This isn’t necessarily a reason not to get involved in the market – just a reminder to take into account all of the potential costs when you’re figuring out how much you can afford to invest.

Overexposure to the stock market

Last, but absolutely by no means least, you should never invest all of your money into the stock market.

As well as risking the loss of every penny you own, having all your money in the markets is tricky if you’re suddenly hit with an unexpected expense, like repairs to your car. If you’re having to sell stocks that are now worth less than you bought them for, you’ve made a loss – an issue that would never arise if you were simply dipping into an easy-access savings account.

Our guide to investing in the stock market with eToro is the perfect practical guide if you’re looking to take the next step.

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