What is a stock?
A stock is a share of legal ownership in a company. When a business sells shares to the public, it divides itself into millions of equal pieces. Buy one and you become a part-owner of that business — however small your fraction — with real rights attached: a claim on future profits, a vote on major decisions, and a stake in the company's growth. This lesson explains what that means in practice, why companies choose to sell ownership rather than borrow, and what buying a single share of Apple or Microsoft actually entitles you to.
Imagine you own a pizza restaurant
It is busy. People love your pizza. But you have a problem: you want to open five more locations, and that costs money you do not have. You could borrow it — take a loan, pay it back with interest — or do something more interesting: sell pieces of the restaurant to other people.
You divide the restaurant into 1,000 equal pieces and keep 600 for yourself. You sell the other 400 to friends, family and strangers who believe in your pizza. They give you money today; in return they own a fraction of everything — the ovens, the brand, the future profits.
Those pieces of ownership are called shares. Issuing them publicly is called going public. And the place where people buy and sell them is the stock market.
Owning shares in a company entitles you to four things:
- A proportional share of profits — paid as dividends when the company distributes earnings.
- Voting rights on major decisions such as who sits on the board or whether to approve a merger.
- Value growth — if the company becomes more valuable, each share is worth more and can be sold for a profit.
- A residual claim on assets — if the company ever closes, shareholders receive what remains after creditors are paid.
Your 1,000-slice pizza restaurant
Each slice = 0.1% ownership. Click a piece to see what it entitles the holder to.
Why would a company give away ownership?
Most beginners never ask this. Companies do not have to sell shares — they could borrow instead. So why give up ownership? There are four big reasons.
They get money without paying it back
A loan must be repaid — with interest, on a schedule, regardless of how the business is doing. Equity is permanent capital: no repayment, no interest. The trade-off is giving up a slice of future profits.
They can raise far more than a bank would lend
When Apple went public in 1980 it raised $101 million in a single day — more than any bank would have offered a four-year-old computer company. Public markets pool capital from millions of investors at once.
They turn employees and investors into partners
Equity grants and stock options give employees a real stake in the upside. If the company succeeds, everyone wins together. That alignment of incentives is one of the most powerful motivational tools in business.
It is the ultimate exit for founders
Building a company for a decade and then taking it public (an IPO) is how most founders convert years of work into liquid wealth.
How does a share get its price?
Here is what surprises most people: there is no formula that calculates the “correct” price of a stock. The price is simply whatever a willing buyer and a willing seller agree on right now.
But what makes buyers and sellers change their minds? Click each event below to see how it typically moves a stock's price — and why.
What moves a stock price?
Click each event to see its effect — and the logic behind it.
Pizza Co. · Hypothetical example
How you actually make money from a stock
Owning a share is nice in theory — but how does it actually put money in your pocket? There are exactly two ways, and most of an investor's lifetime return comes from the first.
1 · Capital gains
If the company becomes more valuable, each share is worth more. Buy at $100, sell at $150, and the $50 difference is a capital gain. The catch: it is only real once you sell. Until then it is a paper gain that can shrink or vanish if the price falls back.
2 · Dividends
Some companies hand a slice of their profits straight to shareholders as a cash dividend — paid every quarter, whether or not you sell. Not all companies pay one: younger firms usually reinvest every dollar to grow faster instead.
Put the two together and you get your total return — price change plus dividends reinvested. Over decades, reinvested dividends compound into a surprisingly large share of the total. The headline number you see for any payer — the dividend yield — tells you how much annual cash a stock pays relative to its price.
What does owning one share of Apple actually mean?
A giant company is divided into billions of shares, so a single share is a vanishingly small slice — but it is a real one. Pick a company and a number of shares to see exactly what you would own, and what it would entitle you to.
Your ownership calculator
Pick a company and a number of shares to see what you would own.
Your ownership stake
$336.91
Invested at today's price
< 0.0001%
Your ownership of Apple
$30.74
Your slice of annual revenue
$8.35
Your share of annual profit
What makes a stock different from a bond, a savings account, or crypto?
You will hear about all of these. A quick map before Lesson 3 goes deeper:
Stock — what it is
- ·Ownership of a business
- ·Large potential upside — grows with the company
- ·Can pay dividends (a share of profits)
- ·Voting rights on major decisions (for most share classes)
- ·Price can fall — even to zero if the company fails
Bond / savings — what it is
- ·Lending money to a company or government
- ·Fixed interest payments — predictable income
- ·Repaid in full at maturity — unless the issuer defaults
- ·Not risk-free — prices fall when interest rates rise
- ·No ownership, no voting rights
- ·Limited upside — you get back what was promised
Quick glossary — six terms every investor uses
These six words appear constantly in financial news and in the rest of this course. One line each:
- Share
- One unit of ownership in a company — buying a share makes you a part-owner.
- Equity
- Ownership in a business expressed as shares; "owning equity" means owning a piece of the company.
- Ticker
- The short symbol that identifies a stock on an exchange — AAPL for Apple, MSFT for Microsoft.
- Exchange
- The marketplace where shares are bought and sold — examples include the NYSE and NASDAQ.
- Dividend
- A cash payment made to shareholders from a company's profits — not all companies pay one.
- IPO
- Initial Public Offering — the moment a company first sells shares to the public on an exchange.
What is market capitalization?
The total market value of a company's shares is its market capitalization. The formula is simple:
Market cap = share price × shares outstanding
The companies listed on stock exchanges are almost incomprehensibly large. Use the slider to explore the scale of the businesses you can buy a piece of, starting from a single share.
Market capitalization explorer
$4.9T
Apple's total market value — the price of all its shares combined
Apple is the reference — all others are measured against it
For context, the GDP of France is about $3 trillion. Apple alone rivals an entire G7 economy.
Now play: Higher or Lower — Market Caps
Test your intuition: is Company A worth more or less than Company B? The surprise is the lesson sticking.
- A stock is a share of legal ownership in a company — buying one makes you a part-owner with real rights.
- Share prices are set by supply and demand alone; there is no formula or official price.
- Market cap (price × shares outstanding) tells you the total market value of a company's shares.
- Stocks carry upside potential but can fall to zero — as an owner you have no promise of repayment and rank last if the company fails, behind bondholders and other creditors.
- Next up: Lesson 2 — why stock prices move every single day, and why record profits can still send a stock down.