What is a share?
A small owner of the company.
To own a share is to own a tiny part of a company. As an owner, you share both the pleasures — a rising price, dividends — and the pains of a falling price or a failure.
In 30 seconds
- A share is a security that gives its holder part-ownership of a company. A shareholder is a small owner of the company.
- The combined value of shares listed on the world’s exchanges was $151.94 trillion at the end of 2025.
- Share prices move up and down, and you can lose the money you invest. If a company goes bankrupt, ordinary shareholders are last in line.
A slice of the cake.
To own a share is to own a tiny part of a company.
Read deeper
What a share is
The investor site of the US Securities and Exchange Commission (SEC) describes stocks as a type of security that gives stockholders a share of ownership in a company. Stocks are also called “equities”.[1]
Companies issue shares to raise money, which they use to pay off debt, launch new products or expand into new markets.[1]
The pleasure comes in two forms.
A rising price and dividends: these are the two main reasons to own shares.
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Price rises and dividends
The SEC’s page gives, as reasons to buy stocks, capital appreciation when the price rises and dividends, when a company distributes part of its profits.[1]
Neither is promised. Both change with a company’s results and with market conditions.
All the world’s shares, added together.
The combined value of shares listed on the world’s exchanges comes to $151.94 trillion.
Combined value of shares listed on the world’s exchanges (end of 2025)
Compiled by the World Federation of Exchanges (WFE). The figure depends on how it is counted.
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The size of the world
According to the World Federation of Exchanges (WFE), global equity market capitalisation was $151.94 trillion at the end of 2025, up 18.5% on the end of the previous year.[2]
The US securities industry association (SIFMA) puts the same 2025 figure at $157.8 trillion.[3] Different exchanges and methods are counted, so there is no single number.
The pain is shared too.
Share prices can fall, and you can lose the money you invest.
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Falling prices and failure
The SEC’s page notes that stock prices move down as well as up, and that there is no guarantee the company will grow and do well, so you can lose the money you invest.[1]
If a company goes bankrupt and its assets are liquidated, common stockholders are the last in line to share in the proceeds.[1]
A scale for reading shares.
A scale for reading shares.
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What ownership means
Which company the share belongs to, and what rights it carries.[1]
Price movement
Prices move up and down. No rise is promised.[1]
The size of the world
How the world’s combined share value changes.[2]
This is not advice
This edition explains how shares work. It does not recommend or compare any share, company or trading venue.
Next question
NEXT QUESTIONMoney you lend, with a promised date attached.NEXT QUESTIONDon’t put all your eggs in one basket.See the Field Notes shelf →What this edition cannot tell you
- The size of each country’s stock market.
- A detailed explanation of how share prices are set.