How the Stock Market Works

The stock market for beginners can look like a wall of flashing numbers, but underneath it is a simple arrangement. Companies sell pieces of themselves to raise money, and those pieces then change hands between investors on regulated exchanges. The price you see is just the last amount a buyer and seller agreed. Everything else, from dividends to indices, builds on that idea.

Why companies issue shares

A growing business needs money for factories, software, staff or acquisitions. It can borrow, which must be repaid with interest, or it can sell ownership. When a private company first sells shares to the public, it holds an initial public offering (IPO) and its shares are listed on an exchange. From then on, most trading is between investors: when you buy a share on the market, the money goes to another investor, not to the company.

Owning a share typically gives you three things: a claim on a proportion of the company's profits, a vote on major decisions such as electing directors, and the right to any dividends the board declares. It does not make you liable for the company's debts; the most you can lose is what you paid.

Exchanges, brokers and custody

Exchanges such as the New York Stock Exchange, Nasdaq and the London Stock Exchange provide the order books where trades are matched, set listing rules and publish prices. Individuals cannot place orders directly; they go through a broker authorised by the national regulator.

The broker usually holds your shares in a nominee or custody account, legally separated from its own assets. That separation matters: if the broker fails, client assets should be returned rather than used to pay the broker's creditors, and many countries add a compensation scheme on top. Checking that a broker is properly authorised is the first step in our guide on how to choose a broker.

After you buy a US share, the trade settles one business day later (T+1), when cash and shares formally swap owners.

How the stock market for beginners actually prices a company

In the short term, prices move with news, rumours, interest-rate expectations and the general mood. Over longer periods they tend to follow what the company earns. A few measurements help connect the two. The figures below are illustrative.

A P/E of 20 means investors are paying $20 for each $1 of this year's profit. Whether that is cheap or expensive depends on how fast profits are expected to grow and how reliable they are. Ratios are starting points for questions, never answers on their own.

Different kinds of shares

Investors and fund providers sort shares into groups that help describe what a portfolio holds. None of these labels is a recommendation; they are shorthand.

• By size: large-cap, mid-cap and small-cap companies, based on market capitalisation. Smaller companies can grow faster but tend to be more volatile and less liquid.
• By style: "growth" shares are expected to increase profits quickly and often pay little or no dividend; "value" shares trade at lower prices relative to their earnings or assets, sometimes for good reason.
• By sector: technology, healthcare, energy, financials, consumer goods and so on. Sectors respond differently to interest rates, commodity prices and the economic cycle.
• By share class: most investors own ordinary (common) shares with voting rights. Some companies also issue preference shares, which usually pay a fixed dividend ahead of ordinary shareholders but carry limited voting rights.

A beginner's research routine

Before buying any individual share, many investors work through the same short routine. It will not tell you what to buy, but it stops you buying something you do not understand.

1. Read the company's description of its business in its latest annual report: what it sells, to whom and where.
2. Look at revenue, profit and cash flow for at least five years. Are they growing, shrinking or erratic?
3. Check debt against cash and yearly profit, and note when large loans must be repaid.
4. Compare valuation measures, such as the P/E and dividend yield, with the company's own history and with similar firms.
5. Read the risk section of the report. Management is required to list what could go seriously wrong.
6. Decide in advance how large the holding will be as a share of your portfolio, and write down why you are buying.

Placing an order

• Market order: buy or sell immediately at the best available price. Simple, but in a fast market or a thinly traded share the price you get can differ from the one you saw.
• Limit order: buy only at or below a price you set (or sell at or above it). You control the price but the order may never fill.
• Stop order: becomes a market order once a trigger price is reached, often used to limit losses. In a sudden gap it can fill well beyond the trigger.

The main US session runs from 09:30 to 16:00 New York time; London from 08:00 to 16:30. Some brokers offer extended hours, but spreads are usually wider outside the main session.

Dividends and total return

Some companies pay part of their profit to shareholders as dividends, often quarterly in the US and half-yearly in the UK. To receive one you must hold the shares before the ex-dividend date; buy on or after it and the payment goes to the seller. On the ex-dividend date the share price usually drops by roughly the dividend amount, because that cash is leaving the company.

Investors usually judge performance by total return: price change plus dividends. Over long periods, reinvested dividends can make up a meaningful share of what an investor earns.

Many brokers offer automatic dividend reinvestment, using each payment to buy more of the same share or fund, sometimes at a reduced dealing charge. Funds often come in two versions: "income" units that pay dividends out as cash, and "accumulation" units that reinvest them inside the fund. Neither is better in itself; the choice depends on whether you need the income now.

Indices and funds

An index tracks a defined group of shares. The S&P 500 follows around 500 large US companies weighted by market value; the Dow Jones Industrial Average follows 30 companies and is weighted by share price; the Nasdaq Composite covers nearly every company listed on Nasdaq. Our Nasdaq index guide explains weighting in detail.

Index funds and ETFs let you buy a whole index in one transaction. For many beginners that is the simplest way to own the stock market: it spreads company-specific risk across hundreds of businesses and usually costs little each year.

The risks that matter

• Company risk: a single business can fail, and its shares can go to zero.
• Market risk: even diversified portfolios can fall sharply in a downturn and take years to recover.
• Currency risk: foreign shares gain or lose value as exchange rates move.
• Behaviour risk: selling in a panic or chasing whatever rose last month does more damage to many portfolios than any single company.
• Cost drag: dealing charges, fund fees and currency conversion compound against you. See trading fees explained.

A common approach is to invest regularly, hold for many years, keep costs low, diversify and avoid borrowing to buy shares. None of that guarantees a profit, but it removes several of the most common ways beginners lose money.

Sources

• US Securities and Exchange Commission, T+1 settlement rule
• S&P Dow Jones Indices, index methodology overviews
• Nasdaq Global Indexes, index methodology overviews