The stock market is where shares of companies are bought and sold between investors

A stock market is a physical or digital place where people and institutions trade ownership pieces of companies. When you buy a share of stock, you own a small part of that company. The stock market sets the price for those shares based on what buyers and sellers agree to pay at any given moment. The largest stock markets in the United States are the New York Stock Exchange (NYSE) and the NASDAQ.

Stock markets exist in most countries. Each country typically has its own exchange or exchanges where local companies list their shares. The mechanics are the same everywhere: a buyer places an order, a seller places an order, and when the prices match, a trade happens. A computer system matches these orders automatically, usually in fractions of a second.

Key Takeaways

  • Stock markets are where shares of publicly traded companies change hands between buyers and sellers, with prices set by supply and demand.
  • When you own stock, you own a fractional stake in a company and may receive dividends if the company pays them, but you also bear the risk if the company loses value.
  • Stock prices move based on company performance, economic conditions, investor sentiment, and news — not on any single person's decision.
  • The stock market operates during set hours on business days, and trades settle within a standard timeframe set by the exchange.

How prices get set in the stock market

Stock prices are not set by the company or by any central authority. Instead, they emerge from the constant flow of buy and sell orders. If many people want to buy a stock and few want to sell, the price rises. If many want to sell and few want to buy, the price falls. This is called supply and demand.

A stock's price also reflects what investors believe the company is worth. If a company reports strong earnings, investors may believe it will grow, so they bid the price up. If a company announces layoffs or loses a major customer, investors may sell, pushing the price down. News, economic reports, and even rumors can shift what investors think a company is worth.

What you own when you buy stock

When you buy one share of a company's stock, you own one fractional piece of that company. If a company has issued one million shares and you own 100, you own 0.01 percent of the company. You have a claim on the company's assets and earnings proportional to your ownership stake.

Some companies pay dividends — regular cash payments to shareholders — from their profits. Not all companies do this. Some reinvest all profits back into the business. Whether a company pays dividends or not, you can still make money by selling the stock for more than you paid for it. You can also lose money if the stock price falls and you sell for less than you paid.

The difference between stocks and bonds

Stocks and bonds are both ways to invest money, but they work differently. When you buy stock, you own a piece of the company. When you buy a bond, you are lending money to a company or government, and they promise to pay you back with interest. A bondholder is a creditor; a stockholder is a partial owner.

If a company goes bankrupt, bondholders get paid before stockholders. But stocks have historically returned more over long periods than bonds, though with more ups and downs along the way. Bonds are generally considered less risky because the payment is fixed and comes before stock dividends.

How the stock market opens and closes

In the United States, the NYSE and NASDAQ are open Monday through Friday, 9:30 a.m. to 4:00 p.m. Eastern Time. This is called regular trading hours. Some brokers allow trading before the market opens (pre-market) or after it closes (after-hours), but volume is much lower and prices can be more volatile.

When the market closes, no new trades happen until it opens the next business day. If major news breaks after hours, the stock price may gap up or down when trading resumes — meaning it opens at a significantly different price than it closed. This is why investors pay attention to news even when the market is closed.

Who participates in the stock market

Stock market participants include individual investors (people buying shares for themselves), institutional investors (pension funds, mutual funds, insurance companies), investment banks, and market makers who facilitate trades. Each group has different goals and time horizons. An individual might hold a stock for decades; a day trader might hold it for minutes.

You do not need to be wealthy to buy stock. Most brokers allow you to buy a single share of most companies, and some allow fractional shares (owning less than one full share). The barrier to entry is low, though the risk of losing money is real.

What moves stock prices day to day

Stock prices move based on new information and changing expectations. Company earnings reports, product launches, management changes, lawsuits, and regulatory decisions all affect how investors value a stock. Broader economic news — interest rate changes, inflation data, employment reports — can move entire market sectors at once.

Investor emotion also plays a role. Fear can cause sudden sell-offs even if company fundamentals have not changed. Optimism can drive prices up ahead of any concrete news. This is why the same stock can trade at very different prices on different days, even when nothing about the company itself has changed.

Frequently Asked Questions

Do I have to use a broker to buy stock?

Yes. Individual investors cannot trade directly on the stock exchange. You must use a brokerage firm, which can be a traditional bank, an online broker, or an investment advisor. The broker executes your order and holds your shares in an account.

What happens if a company goes out of business?

If a company files for bankruptcy, stockholders are last in line to receive anything. Creditors and bondholders are paid first. In most bankruptcies, common stockholders receive nothing. This is why stock ownership carries risk — you can lose your entire investment.

Can the stock market crash?

Yes. A crash is a sudden, steep drop in stock prices across many companies, usually triggered by panic selling or a major economic shock. The 2008 financial crisis and the 2020 COVID-19 market drop are recent examples. Markets have historically recovered from crashes, but recovery takes time.

Is the stock market the same as the economy?

No. The stock market reflects investor expectations about future corporate profits, not current economic conditions. The market can rise while the economy is weak, or fall while the economy is strong. Stock prices are forward-looking; economic data is backward-looking.

How much money do I need to start?

There is no legal minimum. Many brokers allow you to open an account with any amount and buy fractional shares for as little as a few dollars. However, trading costs and account minimums vary by broker, so compare before opening an account.