How the Stock Market Works

The stock market for beginners is usually described as a place to buy and sell shares, which is true but leaves out the useful parts. A stock market is a set of rules and institutions: companies that list, exchanges that match orders, brokers that act for investors, clearing houses that guarantee settlement and regulators that watch all of them. Understanding who does what makes it much easier to judge costs, risks and claims made about "beating the market".

What a share gives you

A share is a unit of ownership in a company. Owning ordinary shares normally gives you three things: a claim on a portion of the company's profits (paid, if the board decides, as dividends), a vote at shareholder meetings, and a claim on what is left if the company is wound up, after lenders and other creditors are paid.

That last point explains why shares are riskier than bonds issued by the same company: shareholders are paid last. It also explains why share prices react to earnings. Investors are valuing a stream of future profits, so news that changes the expected size or certainty of those profits moves the price.

Two simple ratios (illustrative)

If a share costs $80 and the company earned $5 per share last year, the price-to-earnings ratio is 80 ÷ 5 = 16. If it paid $2.40 in dividends per share over the year, the dividend yield is 2.40 ÷ 80 = 3%. Neither number says whether the share is cheap; they only let you compare it with its own history and with similar companies.

How shares get onto an exchange

A company joins a stock exchange through a listing, most often an initial public offering in which it sells new shares to investors. From then on, those shares change hands between investors on the secondary market; the company does not receive money when you buy a share from another investor.

Major exchanges publish fixed sessions. New York's NYSE and Nasdaq trade from 09:30 to 16:00 local time; London from 08:00 to 16:30; Frankfurt's Xetra from 09:00 to 17:30; Tokyo from 09:00 to 11:30 and 12:30 to 15:30; Hong Kong from 09:30 to 12:00 and 13:00 to 16:00. Most also run opening and closing auctions, where orders are collected and matched at a single price.

Brokers, custody and settlement

Individuals reach the exchange through a broker, which is authorised to send orders and must seek the best available result for clients. After a trade, a clearing house steps between buyer and seller so that neither is exposed if the other fails, and settlement transfers the cash and shares. In the US, settlement happens one business day after the trade.

Most brokers hold your shares in a nominee account in their name but for your benefit, separated from the firm's own assets. If a regulated broker fails, client assets should be returned to clients, and many countries operate compensation schemes for shortfalls up to a limit. Check which scheme applies before you choose a provider; our provider checklist covers how.

Shares versus share CFDs

Some platforms offer contracts for difference on shares instead of the shares themselves. A CFD tracks the price but gives no ownership, no vote and usually an adjusted dividend payment. It is normally leveraged (5:1 at most for retail clients in the UK and EU) and incurs overnight financing. It is a trading instrument, not a way to own part of a company.

Order types that matter

• Market order: buy or sell now at the best available price. Fast, but in a thin or fast-moving share the price can be worse than the last quote.
• Limit order: buy no higher or sell no lower than a price you set. You control the price but may not be filled.
• Stop order: becomes a market order once a trigger price trades. Useful for limiting losses, but it can fill well beyond the trigger if the share gaps at the open.

Before placing an order, look at the bid, the ask and the size available at each. How to read the stock market explains quotes, volume and the other numbers on a stock page.

Corporate actions that change what you hold

Companies regularly take decisions that alter the number or value of shares without any trade on your part. Knowing them avoids misreading a price chart.

• Share splits divide each share into several. A two-for-one split halves the price and doubles the number of shares; the value of your holding is unchanged.
• Buybacks use company cash to purchase its own shares, which reduces the number in issue and raises each remaining shareholder's proportion of earnings.
• Rights issues and placings raise new money by issuing more shares. If you do not take up your entitlement, your percentage ownership falls.
• Ex-dividend dates: on the day a share stops carrying the right to the next dividend, its price usually drops by roughly the dividend amount.
• Mergers and takeovers can convert your shares into cash, into shares of another company, or both.

Brokers pass on notices about corporate actions, sometimes with a deadline for choosing an option. Read them; a default choice is applied if you do not respond.

Indices: measuring the market

An index tracks the value of a defined basket of shares. The S&P 500 covers around 500 large US companies weighted by float-adjusted market value; the Dow Jones Industrial Average contains 30 companies weighted by share price; the FTSE 100, DAX, Nikkei 225, ASX 200, Nifty 50 and Sensex play similar roles in their markets. Index funds and ETFs aim to copy an index at low cost, which is one of the simplest ways to own a broad slice of a market.

Where returns come from, and where they go

Over long periods, share returns have come from company earnings growth and dividends, but with large and sometimes prolonged falls along the way. Individual companies can and do fail. Three levers are within your control:

1. Diversification. Spreading money across many companies and sectors reduces the damage one failure can do.
2. Costs. Commissions, spreads, fund charges, currency conversion and platform fees all come straight off your return; see trading fees explained.
3. Time horizon. Money you may need within a few years is exposed to the chance of selling during a fall.

Tax wrappers can also change the outcome. In the UK, for instance, the ISA allowance is £20,000 for the 2026/27 tax year, and gains and dividends inside an ISA are not taxed. Rules differ everywhere, so check your own country's official guidance.

Risks that remain with any stock

• Market risk: most shares fall together in a broad sell-off.
• Company risk: a single business can lose most of its value on bad results, fraud or debt problems.
• Currency risk: buying shares priced in another currency adds exchange-rate moves to share-price moves.
• Liquidity risk: small companies can have wide spreads and few buyers when you want to sell.

Stocks alongside currencies and crypto

For readers who started in forex or crypto, the biggest adjustment is time. Currency traders often measure positions in hours and crypto holders watch prices around the clock, while the case for owning shares is usually made over years. Short-term share trading is possible, but it meets the same problems as short-term trading anywhere: costs, noise and the difficulty of being right often enough to cover both. Leverage is also much lower: 5:1 at most on single-share CFDs for UK and EU retail clients.

For how shares compare with currencies and crypto in structure and protection, see how forex, stocks and crypto markets work.

Sources

• US Securities and Exchange Commission, T+1 settlement
• S&P Dow Jones Indices, index methodology documents
• HM Revenue & Customs, ISA allowances
• Exchange trading-hours notices: NYSE, London Stock Exchange, Deutsche Börse Xetra, Japan Exchange Group, HKEX