How the Stock Market Works

The stock market for beginners can look like a wall of flickering numbers. Underneath, it is a simple arrangement: companies sell pieces of themselves to raise money, and investors then trade those pieces with one another. This guide explains what you buy, where and how it trades, and the habits that tend to matter most for someone investing over decades.

What a share really is

A share is a unit of ownership in a company. Owning one gives you a proportionate claim on the company's profits and assets, and usually a vote at shareholder meetings. If the business grows its earnings over time, the value of that claim tends to grow too. If it fails, shareholders are paid last, after lenders and suppliers, and often receive nothing.

Companies pay profits to shareholders in two ways. They can pay dividends in cash, or they can keep the money to invest in the business, buy back their own shares or pay down debt. Neither route is automatically better; what matters is whether the money earns a good return.

Primary and secondary markets

When a company first sells shares to the public, in an initial public offering, the money goes to the company. That is the primary market. After listing, the shares trade between investors on an exchange, the secondary market. When you buy a share of a large listed company today, you are almost always buying from another investor, not from the company.

Exchanges, hours and settlement

Shares are listed on exchanges such as the New York Stock Exchange and Nasdaq, the London Stock Exchange, Xetra in Frankfurt, the Tokyo Stock Exchange and the Australian Securities Exchange. Each has a regular session in local time: New York from 09:30 to 16:00, London from 08:00 to 16:30, Sydney from 10:00 to 16:00. Our live board shows which are trading now.

After a trade, ownership and cash change hands in a process called settlement. US shares settle one business day after the trade (T+1), a change made in May 2024. Your broker usually holds the shares for you in a nominee account, separate from its own money.

How a trade happens

An exchange keeps an order book of buyers and sellers. The highest price a buyer is offering is the bid; the lowest price a seller will accept is the ask. The difference is the spread, which is a cost to anyone who buys and later sells.

• Market order: buy or sell straight away at the best available price. Quick, but in a thinly traded share or a fast market the price can be worse than expected.
• Limit order: buy or sell only at your chosen price or better. You control the price but the order may not fill.
• Stop order: becomes a market order once a set price is reached, often used to limit losses. It does not guarantee the exit price if the market jumps.

Reading a stock quote

A typical quote page shows more than one price. The last price is the most recent trade. The bid and ask are the best current offers to buy and sell. Volume counts the shares traded so far in the session, and a figure well above normal often means news. The day range and 52-week range show the lowest and highest prices over those periods. Market capitalisation is the share price multiplied by the number of shares, the market's value of the whole company. The price-to-earnings ratio compares the price with a year's profit per share, and the dividend yield compares the yearly dividend with the price.

Check whether the quote is real-time or delayed; free pages are often delayed and usually say so. None of these numbers is a verdict on the company, but together they help you see what the market is currently paying for it.

Indices: measuring the whole market

An index tracks a basket of shares so you can see how a market or segment is doing. The S&P 500 covers about 500 large US companies, weighted by float-adjusted market value. The Dow Jones Industrial Average follows just 30 companies and is price-weighted, so a high-priced share moves it more than a low-priced one. The Nasdaq Composite includes all shares listed on Nasdaq, while the Nasdaq-100 holds the largest non-financial ones. In the UK, the FTSE 100 tracks the largest London-listed companies. When a news report says "the market rose", it usually means one of these.

Funds and ETFs

Buying individual shares means researching each company and accepting that any one can fail. Funds offer another route. An index fund buys every share in an index, or a representative sample, so you own a slice of the whole market in one purchase. An exchange-traded fund (ETF) is a fund whose own units trade on an exchange like a share, so you can buy and sell it during the session.

The key number for any fund is its ongoing charge, also called the expense ratio: a yearly percentage taken from the fund's assets. Small differences compound over time, as our guide to hidden trading costs shows with a worked example.

Dividends and compounding

A company's dividend yield is its yearly dividend divided by the share price. As an illustration, a share priced at $50 paying $2 a year in dividends has a yield of $2 ÷ $50 = 4%. To receive a dividend you must own the share before its ex-dividend date; buy on or after that date and the payment goes to the seller.

Reinvesting dividends buys more shares, which pay more dividends, and so on. That is compounding. As a purely illustrative example, $10,000 growing at 6% a year with everything reinvested would reach about $32,071 after 20 years and about $57,435 after 30. Real returns vary year to year and can be negative; the point is that time does much of the work, and that interruptions and high costs weaken the effect.

Growth, value, large and small

Investors often sort shares into styles. Growth companies reinvest most of their profits to expand and are priced for rising future earnings. Value companies trade at lower prices relative to their current earnings or assets, often because the market expects slower growth. Companies are also grouped by size: large companies tend to be more established, while smaller ones can grow faster but carry more risk and trade less easily. Broad index funds hold all of these styles at once, which is one reason they are a common starting point.

The risks to plan for

• Market risk: broad indices have fallen by a third or more in severe downturns and taken years to recover.
• Company risk: a single share can lose most or all of its value. Holding many companies spreads this risk.
• Currency risk: overseas shares rise and fall with exchange rates, as our forex guide explains.
• Behaviour risk: selling in a panic, or buying because a share has already soared, often does more damage than any single investment.

The stock market for beginners: a sensible way to begin

1. Keep an emergency cash reserve first, so you are never forced to sell shares at a bad time.
2. Write down why you are investing and for how long. Money needed within a few years usually does not belong in shares.
3. Choose a regulated broker, using our ten-point checklist, and check whether a tax-advantaged account is available where you live, such as a UK stocks and shares ISA with its £20,000 yearly allowance for 2026/27.
4. Consider broad, low-cost funds as a core before experimenting with individual companies.
5. Invest regularly and review occasionally, not daily.

Sources

• US Securities and Exchange Commission, T+1 settlement cycle
• S&P Dow Jones Indices, index methodology documents
• Nasdaq, Nasdaq-100 index methodology
• HM Revenue & Customs, Individual Savings Account allowances 2026/27