A stock is a unit of ownership in a company. Buy one share and you own one slice of everything that company is worth and everything it owes, along with a claim on its future profits. You do not lend the company money, you do not get a guaranteed return, and you are last in line if it fails.
What a share actually is
Companies divide their ownership into shares. If a company has 100 million shares outstanding and you own 1,000, you own 0.001% of the business. That fraction entitles you to a share of the profits the board chooses to distribute, a vote on certain matters at the annual meeting, and any information regulators require companies to publish.
It does not entitle you to a fixed payment, to your money back on demand, or to a say in daily decisions. Those belong to the company and its board.
Where the shares come from
Two different markets, often confused:
- Primary market. The company issues new shares and receives the cash 鈥?an initial public offering or a follow-on sale. The money goes into the business.
- Secondary market. Investors trade existing shares with each other on an exchange. The company receives nothing; the seller receives the price.
Almost every share a retail investor buys is bought in the secondary market. When the price rises, the company does not automatically get richer 鈥?its shareholders do.
Market capitalisation, in one line
The size of a company in market terms is its share price multiplied by the number of shares outstanding.
Market cap = price per share 脳 shares outstanding
If a company trades at $25 with 400 million shares outstanding, its market capitalisation is $10 billion. A $25 price alone tells you nothing about whether the company is large or small; the share count does that work. Investor.gov publishes a glossary entry for this measure if you want the official wording.
What actually moves the price
Over a single day, price is set by the balance of buyers and sellers. Over years, three things dominate:
- Earnings and expectations. A company that earns more than expected tends to rise; one that misses tends to fall. What matters is the gap between results and what the market already assumed.
- Interest rates. When safe bonds pay more, future profits are worth less today, which tends to press on valuations. This is the same discounting idea behind bond prices and yields.
- Risk appetite. In anxious markets, investors demand a bigger discount for uncertainty, and prices fall even when nothing about the business changed.
What you get, and what you do not
| You get | You do not get |
|---|---|
| A claim on profits paid as dividends, if the board declares one | A guaranteed dividend 鈥?the board can cut or suspend it |
| A vote on directors and major matters | A say in daily management |
| Limited liability: you cannot lose more than you invested | Priority over lenders if the company fails |
| Any capital gain if the price rises | Your original money back on demand |
Two risks sit underneath that table. Dilution: if the company issues more shares, your slice of the same business gets smaller. Single-company risk: one company can fail completely while the overall market rises.
How most people actually own stocks
Owning individual shares means tracking one business closely. Most long-term savers instead own hundreds of companies at once through a fund, which removes the single-company risk and the research burden. The trade-off 鈥?control and fees versus diversification 鈥?is the subject of index fund vs ETF and expense ratios.
Prices also swing far more than the underlying businesses change. That gap between price and value is what volatility measures, and it is why the holding period matters more than the entry price.
Frequently asked questions
Do I own part of the company’s assets?
In a legal sense you own equity, a residual claim on the company after all debts are paid. You cannot walk in and take a chair; the claim only becomes concrete if the company is sold or liquidated, and in a liquidation shareholders are paid last.
What is the difference between a stock and a share?
Nothing meaningful for a retail investor. “Stock” refers to the ownership interest in general; a “share” is one unit of it. You own shares of a stock.
Can a share price go to zero?
Yes. A company can fail, and common shareholders can lose the entire investment. This is the reason diversification and position sizing exist.
Do I need a lot of money to start?
No. Many brokers allow fractional shares, and funds can be bought in small amounts. The bigger constraint is time horizon, not the starting balance.
Sources and further reading
Reference sources for the definitions and rules used on this page:
- Investor.gov (SEC) 鈥?Stocks
- Investor.gov (SEC) 鈥?Market capitalisation
- Investor.gov (SEC) 鈥?Dividend
Reviewed 29 October 2026. This article is educational and is not financial advice. See our disclaimer.
