A jargon-free explanation of how the stock market works, including why prices move, how trades happen, and what it means for your investments.
- Not all stocks pay dividends, but those that do provide a regular income stream in addition to any price appreciation.
- The stock market can feel like an impenetrable world of numbers, jargon, and complexity.
- But the core concept is surprisingly simple: the stock market is a place where people buy and sell small ownership stakes in businesses.
The stock market can feel like an impenetrable world of numbers, jargon, and complexity. But the core concept is surprisingly simple: the stock market is a place where people buy and sell small ownership stakes in businesses. Understanding how it works, in plain terms, removes much of the intimidation and makes you a more confident investor.
What a Stock Actually Is
When a company wants to raise money, one option is to sell ownership shares to the public. Each share represents a tiny fraction of ownership in the company. If a company has 1 million shares outstanding and you buy 100 of them, you own 0.01% of the company. As a shareholder, you have a proportional claim on the company’s future profits and assets.
Companies sell shares initially through an Initial Public Offering (IPO), where the company sells shares directly to investors for the first time. After the IPO, those shares trade between investors on the stock exchange. When you buy a stock through your brokerage, you are almost always buying it from another investor who is selling, not from the company itself.
Why Stock Prices Move
Stock prices are determined by supply and demand. If more people want to buy a stock than sell it, the price rises. If more people want to sell than buy, the price falls. This constant push and pull happens millions of times per second across thousands of stocks, driven by investors’ collective assessment of what each company is worth.
What influences those assessments? Company earnings and revenue growth, expectations for future performance, economic conditions, interest rates, industry trends, news and events, and investor sentiment. Some of these are rational and data-driven. Others are emotional and unpredictable. This mixture of rationality and emotion is what creates the short-term volatility that makes stock prices bounce around daily while still trending upward over the long term.
Stock Exchanges
Stocks are traded on exchanges, which are essentially organized marketplaces that match buyers and sellers. The two largest U.S. exchanges are the New York Stock Exchange (NYSE) and the Nasdaq. When you place an order through your brokerage app, your brokerage routes it to an exchange where it is matched with a corresponding order from another investor.
Modern stock trading is almost entirely electronic. The iconic image of traders shouting on a trading floor is largely historical. Today, trades are executed by computers in milliseconds. This electronic infrastructure makes it possible for anyone with a brokerage account to buy or sell virtually any publicly traded stock instantly during market hours.
Indices: Measuring the Market
Stock market indices are benchmarks that track the performance of a group of stocks. The S&P 500 tracks the 500 largest U.S. companies by market capitalisation. The Dow Jones Industrial Average tracks 30 large companies. The Nasdaq Composite is heavily weighted toward technology companies. When news reports say “the market” went up or down, they are usually referring to one of these indices.
These indices are useful as shorthand for overall market performance, but they do not perfectly represent every investor’s experience. Your portfolio, depending on what you own, may perform differently than any particular index on any given day.
How Investors Make Money
There are two ways to make money from stocks. Capital appreciation is when the stock price increases above what you paid. If you buy a share at $50 and it rises to $75, you have a $25 gain (realized when you sell). Dividends are periodic cash payments that some companies distribute to shareholders from their profits. Not all stocks pay dividends, but those that do provide a regular income stream in addition to any price appreciation.
Over the long term, the stock market has returned an average of roughly 10% per year before inflation, combining both capital appreciation and dividends. This long-term average masks enormous variation from year to year, but for patient investors, the stock market has been the most reliable wealth-building vehicle available.
Risk and Time
The stock market carries real risk. Prices can drop significantly, and individual companies can lose most or all of their value. Diversification, owning many stocks through index funds rather than betting on individual companies, dramatically reduces this risk. And time is the ultimate risk mitigator. While any single year can produce losses, there has never been a 20-year period where a diversified U.S. stock portfolio lost money.
Stock market investing involves risk, including loss of principal. Past performance does not guarantee future results. See our financial disclaimer for important disclosures.
A worked example
Imagine investing $500/month for 30 years at an average 8% annual return. Total contributions: $180,000. Final balance: roughly $745,000. The first $180,000 is yours; the other $565,000 is compounded growth. Now imagine starting 10 years later - same $500/month for 20 years at 8%: contributions $120,000, balance $295,000. The 10 years cost you about $450,000 in foregone growth. Time in the market beats timing the market by an enormous margin.
Common mistakes to avoid
- Trying to time the market. Studies consistently show that missing just the 10 best market days over 20 years cuts returns roughly in half. You can't reliably know which days those will be.
- Picking individual stocks based on news or tips. By the time it's news, the price already reflects it. Index funds aren't exciting but they outperform most retail stock-picking by a wide margin.
- Panic-selling in a downturn. Selling locks in losses. Markets have always recovered. The investors who do worst are the ones who sell low and re-buy high.
Frequently asked questions
How much money do I need to start investing?
Less than you think. Most major brokerages (Fidelity, Schwab, Vanguard) have no minimum balance. Fractional shares mean you can buy a $1 slice of any stock or ETF. Realistically, $50-100/month into a low-cost index fund is enough to start building real wealth over decades.
Is it too late to start investing at 40, 50, or 60?
No - but the strategy changes. At 40 you still have 25 years of compounding ahead. At 50 the focus shifts to maximizing 401(k) contributions (you can contribute extra after age 50). At 60 it's about preserving what you have and shifting to a more conservative allocation. The worst day to start was 20 years ago; the second-best is today.
Should I invest in individual stocks or index funds?
Index funds for nearly everyone. Over 20-year periods, 80%+ of professional fund managers fail to beat the index - and they have PhD analysts and millions in research budgets. A target-date retirement fund or a total-market index ETF will outperform what almost any retail investor can do picking individual stocks.
What is the safest investment?
FDIC-insured savings accounts and CDs (up to $250,000 per bank per ownership type) and US Treasury bills/bonds are the safest. They won't make you rich but they won't lose principal. For real (inflation-adjusted) safety, TIPS and I-Bonds protect against inflation, which traditional bonds don't.
How much should I have in stocks vs bonds?
A starting heuristic is 'your age in bonds' - so a 30-year-old holds 70% stocks / 30% bonds. Many financial planners now suggest something more aggressive given longer lifespans: 110 or 120 minus your age in stocks. Target-date funds do this automatically based on your retirement year.
Where this guide fits in
This article is part of the Chase The Dollar editorial library of practical money guides. We update guides as rules and rates change. If you spot a mistake or want us to cover a topic, the contact form is the fastest way to reach us.