What Are Stocks and How Do They Work

When you buy a stock — also called a share or equity — you are not buying a lottery ticket or a number on a screen. You are buying a small piece of a real business: a claim on part of its assets and part of its profits, along with a voice in how it is run. Understanding this single idea is the foundation of nearly everything else in investing.

This guide explains stocks from first principles: what ownership actually means, why companies issue shares, how shareholders get paid, what moves prices day to day, and what the evidence says about trying to beat the market.

What Is a Stock?

A share of stock is an instrument that signifies an ownership position — called equity — in a corporation, together with a claim on a proportional share of that corporation's assets and profits. Most stocks also carry voting rights, giving shareholders a proportional vote in certain corporate decisions, such as the election of directors.

The key word is fractional. A single share represents ownership of the corporation in proportion to the total number of shares outstanding. If a company has one million shares and you own one, you own one millionth of the company — its earnings, its voting power and, in a liquidation, its remaining assets (after all senior claims are settled).

One subtlety trips up many beginners: owning common stock does not mean you directly own any of the company's assets. You own a fractional interest in the company, and it is the company that owns the factories, offices and cash. Your claim is indirect — which is exactly why, in a bankruptcy, shareholders stand last in line.

Why Companies Issue Shares — and Where They Trade

Companies issue shares primarily to raise capital. Selling ownership stakes brings in cash to build factories, hire staff, develop products or expand into new markets — without taking on debt. A first public sale of shares is called an IPO, which we cover in a separate guide.

There is a trade-off: as new shares are issued, the ownership and rights of existing shareholders are diluted in exchange for the cash that sustains or grows the business. If you owned 1% of a company and it doubles the share count, your slice shrinks to 0.5% — the hope is that the new capital grows the whole pie by more than your slice shrank.

Companies can also go the other way and buy back their own stock, reducing the number of shares outstanding and concentrating ownership among remaining holders.

Once issued, shares live mostly on the secondary market: stock exchanges where investors trade with each other, and the company itself typically receives no money from these transactions. Buying and selling can also happen privately, off-exchange. Either way, transactions are closely overseen by governments and regulatory bodies whose job is to prevent fraud and protect investors.

Common Stock vs. Preferred Stock

Not all shares are equal. The two main types differ in rights, priority and risk.

Common stock gives the holder the right to share in the company's profits and to vote on matters of corporate policy and the composition of the board of directors. But common stockholders sit at the bottom of the payout hierarchy: they receive dividends only after obligations on preferred stock are met, and in a liquidation they are paid only after creditors (including employees), bondholders and preferred stockholders. When a company fails through bankruptcy, common stockholders typically receive nothing.

Preferred stock usually does not carry voting rights, but it is legally entitled to receive a certain level of dividend payments before any dividends can be paid to other shareholders — a trade of voice for priority.

Because common stock is more exposed to the risks of the business than bonds or preferred shares, it offers greater potential for capital appreciation. Over the long term, common stocks have tended to outperform more secure investments despite their short-term volatility — the extra risk is the price of the extra return. For context on the alternatives, see our guide to bonds and bond ETFs.

Shareholder Rights

Owning shares is not just a financial position; it comes with legal rights, set out in corporate law and the company's own bylaws. The most familiar is the right to vote at general meetings, typically one vote per share, including the election of the board of directors and votes on major corporate decisions.

In practice, most retail investors hold too few shares for their individual vote to matter, and many never attend meetings. But the rights still matter: they are part of what you own, they underpin corporate accountability, and they can become genuinely significant in contested situations such as takeover bids. Your economic rights — the claim on earnings and assets — are where most of your return actually comes from.

How Investors Make Money: Dividends and Capital Appreciation

When you own stock, most of your return comes through one of two channels.

Dividends are cash distributions of company profits. Capital appreciation is the increase in the share price between purchase and sale. Not all companies pay dividends — many growing businesses reinvest profits back into the business instead, on the theory that a euro retained and reinvested at high returns is worth more to owners than a euro paid out today.

A worked example: suppose you buy 50 shares at $10 each — a $500 investment. The share price later rises to $15, so your holding is now worth $750: a $250 gain from capital appreciation. If the company also pays a $2 dividend per share, you receive $100 in cash. Your total return is the combination of the two.

Two cautions. First, dividends are not guaranteed — a company can cut or suspend them when profits fall. Second, over long horizons, capital appreciation tends to be the main growth engine, which is why the long-term case for stocks rests on businesses growing their earnings. For a deeper treatment, see understanding dividends.

What Moves Stock Prices

At any moment, prices are set by supply and demand: what buyers are willing to pay and sellers are willing to accept. But what shapes those willingness-to-pay levels?

In an efficient market, prices would be determined primarily by fundamentals — an earnings base such as earnings per share (EPS), multiplied by a valuation multiple such as the P/E ratio. Higher expected growth earns a stock a higher multiple; a higher discount rate — driven by perceived risk, inflation and interest rates — earns a lower multiple. Our P/E ratio basics guide unpacks this further.

In practice, prices move for many reasons beyond any single company's performance. Market trends, economic conditions and even news headlines can move prices in the short term. Research has suggested that overall market and sector or industry movements — as opposed to a company's individual performance — account for about 90% of a stock's movement. This is a core argument for diversification: if most of your risk comes from the market itself, holding many companies does not remove it, but holding many types of assets can soften it.

The crucial distinction is time horizon. Day to day, prices are noisy and often disconnected from the business. Over the long term, performance is typically tied to the underlying company's financial strength and its ability to grow. Volatility is the toll you pay to reach the long-run returns.

The Efficient Market Hypothesis

The Efficient Market Hypothesis (EMH) states that share prices reflect all available information, making consistent generation of excess returns — "alpha" — impossible. If prices already incorporate what is knowable, then actively hunting for mispriced stocks should not reliably beat simply owning the market.

EMH comes in three forms:

• Weak form: past prices are already reflected in today's price — so technical analysis based on price history adds nothing.
• Semi-strong form: all public information is in the price — so fundamental analysis of published reports cannot consistently add value either.
• Strong form: all information, public or private, is in the price — the most demanding version, and the least supported by evidence.

The practical implication is that a low-cost, passive strategy will usually achieve the best long-term results for most investors, which is the logic behind index funds and ETFs. We explore this in passive vs active investing.

EMH has critics, and for good reason. The 1987 crash — when the Dow Jones Industrial Average fell by over 20% in a single day — is often cited as evidence that markets are not always efficient, since no comparable amount of new information arrived to justify such a collapse. Bubbles and panics suggest prices can detach from fundamentals for extended periods. A reasonable middle view: markets are mostly efficient enough that beating them is very hard, but not so efficient that prices are always sensible.

Key takeaways

• A stock is fractional ownership of a corporation — a proportional claim on its earnings, assets and governance, not a direct claim on its property.
• Companies issue shares to raise capital (diluting existing holders) and can buy shares back; most trading happens on regulated secondary markets.
• Common stock offers voting rights and the highest growth potential but the lowest payout priority; preferred stock trades voting power for dividend priority.
• Returns come from dividends and capital appreciation; dividends are not guaranteed, and long-term growth is driven mainly by growing earnings.
• Short-term price moves are largely noise — market and sector factors explain roughly 90% of a stock's movement — while long-term results track business fundamentals.
• The Efficient Market Hypothesis argues prices reflect available information, favouring low-cost passive investing for most long-term investors, though events like the 1987 crash show markets are not perfectly efficient.

Educational only — not personalised investment advice.