What is a stock?
A stock (or share) is a small piece of ownership in a company. Own one share of Coca-Cola and you own a tiny slice of every factory, brand and future profit of Coca-Cola.
What a share gives you
💵 A share of profits
Paid as dividends (if the company pays them) or reinvested to grow the business.
🗳️ A vote
At the annual general meeting: electing the board, approving big decisions. One share, one vote (usually).
🧾 A claim on assets
If the company is wound up, shareholders are paid last, after employees, tax authorities and lenders.
How you earn money from a stock
Why do share prices move?
Every second, buyers and sellers agree on a price. In the short run, the price reflects news, emotions and supply and demand. In the long run, it tends to follow what the business actually earns. In Benjamin Graham's famous words: "In the short run, the market is a voting machine; in the long run, it is a weighing machine."
- Company results: profits above or below what investors expected.
- Interest rates: higher rates make safe savings more attractive and future profits worth less today (the DCF lesson explains why).
- The economy: recessions hurt most companies' sales.
- Sentiment: fear and greed can push prices far from value for a while.
Kinds of shares
| Common (ordinary) shares | The normal kind: votes and variable dividends. |
| Preferred shares | Usually no vote, but a fixed dividend paid before common shareholders get anything. Somewhere between a share and a bond. |
| Share classes | Some companies have several classes with different voting rights (Alphabet: GOOGL with votes, GOOG without). |
| ADRs | Certificates that let a foreign company's shares trade in the US in dollars (e.g. Toyota as "TM"). |
Tickers and indices
Each listed share has a short code, the ticker. Outside the US a suffix shows the exchange: 7203.T (Toyota, Tokyo), SAP.DE (SAP, Germany), MC.PA (LVMH, Paris), H2O.RO (Hidroelectrica, Bucharest). An index follows a basket of shares to show how "the market" is doing:
| Index | What it contains |
|---|---|
| S&P 500 | About 500 of the largest US companies, weighted by size |
| Dow Jones Industrial Average | 30 large US companies; the oldest famous index (1896) |
| Nasdaq-100 | 100 large non-financial companies on Nasdaq, mostly technology |
| Euro Stoxx 50 | 50 large eurozone companies |
| BET | The most traded companies on the Bucharest Stock Exchange |
The risk side
Stocks have historically given higher long-term returns than savings accounts or bonds, and that is the reward for real risk:
- In the 2008–2009 financial crisis, the S&P 500 fell by more than half from its peak.
- In February–March 2020 (Covid), it fell about a third in roughly one month.
- Single companies can go to zero: Enron (2001) and Lehman Brothers (2008) were both large, famous and admired before they collapsed.
Show the answer
2 billion × $50 = $100 billion. After a 10% rise the price is $55 and the market cap $110 billion. The company itself received nothing: the gain belongs to whoever owns the shares.