The stock market can seem like a confusing world of tickers and charts, but the basic idea is simple. Understanding how the stock market works helps you invest with more confidence and less fear when headlines turn negative.
What is a stock?
A stock, or share, is a small piece of ownership in a company. If a company has one million shares and you own 1,000, you own 0.1% of it. As an owner, you may benefit if the company grows and its profits rise, and some companies also share profits through dividends.
Why companies sell shares
Companies sell shares to raise money for growth, such as building factories, hiring staff or developing products. The first time a company sells shares to the public is called an initial public offering (IPO). After that, investors buy and sell those shares among themselves on stock exchanges.
Stock exchanges
Exchanges are marketplaces where buyers and sellers trade shares. Examples include the New York Stock Exchange and Nasdaq in the US, the London Stock Exchange in the UK, the Toronto Stock Exchange in Canada and the Nigerian Exchange (NGX) in Nigeria. Today, almost all trading happens electronically.
How prices are set
Prices move based on supply and demand. If more people want to buy a stock than sell it, the price rises; if more want to sell, it falls. Demand changes with company earnings, economic news, interest rates and investor sentiment. In the short term, prices can swing for emotional reasons. Over the long term, they tend to follow company profits.
What is a market index?
An index tracks a group of stocks to show how part of the market is performing. The S&P 500 follows 500 large US companies, the FTSE 100 tracks large UK companies, the S&P/TSX Composite tracks major Canadian companies, and the NGX All-Share Index covers Nigerian stocks. When people say “the market is up 1%”, they usually mean a major index.
How you buy and sell stocks
- Open an account with a regulated broker or investing app.
- Deposit money.
- Search for a stock or fund by name or ticker.
- Place an order: a market order buys at the current price; a limit order sets the maximum you will pay.
- Hold your investment and monitor it occasionally.
Bull and bear markets
| Term | Meaning |
|---|---|
| Bull market | A sustained period of rising prices |
| Bear market | A fall of about 20% or more from a recent high |
| Correction | A fall of about 10% from a recent high |
| Volatility | How sharply prices move up and down |
The risks
Stocks can fall significantly, and individual companies can fail entirely. That is why most beginners use diversified index funds rather than picking single stocks. Historically, broad markets have risen over long periods, but there have been many years of losses along the way. Only invest money you will not need for at least five years.
How beginners usually take part
- Buy a low-cost index fund or ETF that holds hundreds of companies.
- Invest a fixed amount every month, known as dollar-cost averaging.
- Use tax-advantaged accounts such as an IRA, ISA or TFSA.
- Ignore daily noise and review once or twice a year.
See how regular investing could grow over time with our Compound Interest Calculator.
Common beginner mistakes
- Buying a stock because it is trending on social media.
- Selling in panic during a market fall.
- Putting all your money into one company.
- Trading too often and paying unnecessary fees or taxes.
What moves the stock market day to day
Once you understand how the stock market works, daily headlines make more sense. Common drivers include:
- Company earnings reports: results versus expectations.
- Interest rate decisions: central bank moves affect borrowing costs and valuations.
- Economic data: jobs reports, inflation and growth figures.
- Global events: elections, conflicts and supply disruptions.
- Investor sentiment: fear and optimism can push prices beyond fundamentals in the short term.
For long-term investors, most daily moves are noise. Historically, staying invested through downturns has mattered more than reacting to headlines. Set up automatic contributions and review your portfolio once or twice a year rather than every day.
For official, up-to-date guidance, see Investor.gov’s guide to how stock markets work.
Frequently asked questions
Can you lose all your money in the stock market?
With a single stock, yes. With a broad, diversified index fund, losing everything is extremely unlikely, though values can fall sharply in the short term.
How much money do I need to start investing in stocks?
With fractional shares, you can start with a few dollars.
What time is the stock market open?
It depends on the exchange. US markets are generally open on weekdays from 9:30 a.m. to 4 p.m. Eastern Time, excluding holidays.
How the stock market works: key takeaways
- Stocks are small pieces of ownership in companies.
- Prices move with supply, demand and company profits.
- Indexes track groups of stocks to measure the market.
- Diversified, long-term investing reduces risk for beginners.
Last reviewed: October 2026. This article is general education, not personal financial, tax or legal advice. Rules, rates and limits change, so check official sources or speak to a qualified professional before making decisions. See our Financial Disclaimer.