How the Stock Market Works

The stock market for beginners can feel like a casino with better lighting, but underneath the noise it is a well-regulated system for transferring slices of company ownership. Understanding how that system works is the best defence against both overconfidence and the scams that borrow its language.

What you own when you buy a share

A share is a unit of ownership in a company. Owning shares normally gives you a claim on part of the company's profits, a vote at shareholder meetings and, if the company is sold, a share of the proceeds. It does not give you a right to your money back. If the company fails, shareholders are paid last, often nothing.

Share prices move because investors constantly re-estimate what a company will earn in the future and how much they are willing to pay for those earnings today. Interest rates matter too: when safer assets pay more, investors tend to demand more from riskier ones.

Primary and secondary markets

A company raises money when it first sells shares to the public in an initial public offering (IPO) or in later share issues. That is the primary market. Almost all everyday trading happens in the secondary market, where investors buy and sell existing shares from each other. When you buy a share on an exchange, your money goes to another investor, not to the company.

Exchanges and their hours

Shares are listed on regulated exchanges, each with fixed weekday sessions in local time:

News that breaks while an exchange is closed is priced in at the next open, often with a jump called a gap. Some brokers offer pre-market and after-hours trading in US shares, where prices can be thinner and spreads wider.

How a broker fits in

You cannot place orders on an exchange directly; a licensed broker does it for you. In most major markets the broker must hold your shares and cash separately from its own assets, usually in a nominee account registered in the broker's name for your benefit. If the broker fails, those assets should be returned to clients, and several countries run compensation schemes for shortfalls up to a limit.

Be clear on what the broker sells. Some platforms that look like share-dealing apps actually offer CFDs on shares, so you hold a contract rather than the share. The distinction is explained in our markets overview, and how to choose a broker lists the documents that reveal it.

Order types in plain terms

• Market order: buy or sell now at the best available price. Fast, but the price you get can differ from the one you saw, especially in thinly traded shares.
• Limit order: buy at or below, or sell at or above, a price you set. Price control, but no guarantee of a fill.
• Stop order: becomes a market order once a trigger price is reached. Often used to limit losses, but it can fill well beyond the trigger if the price gaps.

Since May 2024, US share trades settle one business day after the trade (T+1), so the shares and the cash formally change hands the next working day.

Reading a share quote

A broker's quote screen shows more than one price. The bid is what buyers are currently offering and the ask is what sellers want; you buy at the ask and sell at the bid. For large, heavily traded companies the gap is often tiny. For small companies it can be several percent, which is a cost paid the moment you buy.

You will also see the day's trading volume, the previous close and often the market capitalisation, which is the share price multiplied by the number of shares in issue. A price of $400 does not make a company more valuable than one priced at $20; only the market capitalisation compares their size. Ratios such as price to earnings (P/E) relate the price to the company's profits, and a very high ratio means investors are paying up for expected growth that may or may not arrive.

Single shares, funds and ETFs

Buying one company's shares concentrates your risk in that company's fortunes. Funds pool money from many investors and spread it across many holdings. Actively managed funds pay a manager to choose investments; index funds and most exchange-traded funds simply follow an index at lower cost. ETFs trade on an exchange like a share, with a bid, an ask and the same trading hours. Every fund charges an annual fee, shown as an ongoing charge or expense ratio, which is taken from the fund's value rather than billed to you, so it is easy to overlook.

Dividends: a worked example (illustrative numbers)

Some companies pay part of their profits to shareholders as dividends. Suppose you own 200 shares bought at $40 each, an $8,000 holding, and the company pays $0.30 per share every quarter.

• Each quarter: 200 × $0.30 = $60.
• Each year, if the dividend is unchanged: $60 × 4 = $240.
• Yield on your purchase price: ($0.30 × 4) ÷ $40 = 3%.

Dividends are never guaranteed; companies cut them when profits fall. Tax may be withheld on foreign dividends, and the fees guide covers the currency conversion charges that can apply when you buy shares listed abroad.

Indices: measuring the whole market

An index tracks a defined group of shares. The S&P 500 follows about 500 large US companies weighted by float-adjusted market value; the Dow Jones Industrial Average tracks 30 companies weighted by share price; the Nasdaq-100 covers large non-financial companies listed on Nasdaq; the FTSE 100, DAX, Nikkei 225, ASX 200, Nifty 50 and Sensex do similar jobs elsewhere. You cannot buy an index directly, but index funds and exchange-traded funds (ETFs) aim to match one, spreading your money across every member.

That spreading is the main tool beginners have against single-company risk. A holding in one company can fall to zero; a diversified fund rarely falls as far, though it can still drop sharply in a broad sell-off.

Stock market for beginners: rules worth knowing

• UK tax wrappers: gains and income inside a Stocks and Shares ISA are tax-free, within an overall annual ISA allowance of £20,000 for 2026/27.
• US day-trading rules: the long-standing $25,000 pattern day trader minimum is being replaced. The SEC approved FINRA's new approach, based on intraday margin requirements, on 14 April 2026, with an effective date of 4 June 2026. Brokers may still apply their own limits.
• Leverage on shares: UK and EU retail CFD clients are limited to 5:1 on individual shares.

The risks, stated plainly

Share prices can fall for long periods, and individual companies can fail completely. Newsletters, social media groups and "insider tips" promising quick gains are a common route into pump-and-dump schemes, where promoters sell to the buyers they attract. If someone you do not know is urging you to buy a small, obscure share quickly, read our scam guide first.

Sources

• US Securities and Exchange Commission, T+1 settlement rule
• US Securities and Exchange Commission approval of FINRA pattern day trading rule changes, 14 April 2026
• HM Revenue & Customs, ISA allowances 2026/27
• UK Financial Conduct Authority, CFD rules for retail clients