What the stock market is

The stock market is a system where shares of companies are bought and sold between investors. When you own a share, you own a small piece of that company. The stock market is not one building or one place — it is a network of exchanges, brokers, and electronic systems that connect buyers and sellers.

The two largest stock exchanges in the United States are the New York Stock Exchange (NYSE) and the NASDAQ. Both operate during regular business hours on weekdays. When you hear news reports say "the market is up" or "the market is down," they are usually referring to major indexes like the S&P 500, which track the price movements of hundreds of large companies.

Stock prices change throughout the day based on supply and demand. If many people want to buy a stock and few people want to sell it, the price goes up. If many people want to sell and few want to buy, the price goes down. This happens thousands of times per second across all the stocks being traded.

Key Takeaways

  • A stock represents ownership in a company, and the stock market is where those shares are bought and sold between investors.
  • Stock prices move based on supply and demand — when more people want to buy than sell, prices rise, and when more want to sell than buy, prices fall.
  • The NYSE and NASDAQ are the two main U.S. stock exchanges, and they operate during regular business hours on weekdays.
  • You need a brokerage account to buy or sell stocks, and your broker executes the trade on an exchange on your behalf.
  • Stock ownership can provide returns through price increases and through dividends, which are payments some companies make to shareholders.

How you buy and sell stocks

To buy or sell a stock, you need a brokerage account. A broker is a company licensed to buy and sell securities on your behalf. You open an account with a broker, deposit money, and then place an order to buy a specific stock at a price you choose or at the current market price.

When you place an order, your broker sends it to the exchange where that stock trades. The exchange matches your order with a seller's order. Once the orders match, the trade is executed — you own the shares and the seller receives the cash. This process usually takes a few seconds, though the settlement (the actual transfer of money and shares) takes two business days.

You can place different types of orders. A market order buys or sells when ready at whatever the current price is. A limit order lets you set a maximum price you will pay to buy or a minimum price you will accept to sell — the trade only happens if the stock reaches that price. Most brokers charge a commission or fee for each trade, though many now offer commission-free trading on stocks.

Why stock prices move

Stock prices reflect what investors believe a company is worth right now and what it might be worth in the future. When a company reports strong earnings, investors often become more optimistic and buy more shares, pushing the price up. When a company reports disappointing results or faces bad news, investors may sell, pushing the price down.

Broader economic conditions also move stock prices. If interest rates rise, investors may move money out of stocks into bonds or savings accounts. If the economy is growing and unemployment is low, investors often feel confident and buy more stocks. Major news events — a war, a pandemic, a change in government policy — can cause sudden price swings across many stocks at once.

Individual investor psychology plays a role too. Fear and greed drive buying and selling decisions. When prices are rising and investors feel optimistic, they buy more, which pushes prices higher. When prices are falling and investors feel scared, they sell, which pushes prices lower. This cycle of emotion and trading is normal and happens every day.

Dividends and other ways stocks return money

Some companies pay dividends — regular cash payments to shareholders. A company might pay a dividend quarterly or annually. The dividend is usually expressed as a dollar amount per share or as a percentage of the stock price, called the dividend yield. Not all companies pay dividends; many reinvest profits to grow the business instead.

The other way stocks return money to you is through price appreciation. If you buy a stock at $50 and it rises to $75, you have a $25 gain per share. You only realize that gain when you sell. If the stock falls to $40, you have a loss. Unlike dividends, which are paid to you whether the price moves or not, price gains or losses depend entirely on whether you sell at a higher or lower price than you bought.

Stock indexes and how they measure the market

A stock index is a collection of stocks grouped together to measure how a section of the market is performing. The S&P 500 tracks 500 large U.S. companies. The Dow Jones Industrial Average (often called "the Dow") tracks 30 very large companies. The NASDAQ Composite includes all stocks listed on the NASDAQ exchange, which tends to have more technology companies.

When news reports say "the market is up 2 percent," they are usually referring to one of these indexes. An index does not move because of one stock — it moves because of the combined movement of all the stocks in it. If most stocks in the S&P 500 are rising, the index rises. If most are falling, the index falls. Watching an index gives you a quick sense of whether investors are generally feeling optimistic or pessimistic.

The difference between stocks and bonds

Stocks and bonds are both securities you can own, but they work differently. When you buy a 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. Bonds are generally considered less risky than stocks because the borrower has a legal obligation to repay you, while a stock's value depends on the company's performance and investor sentiment.

Stocks have higher potential returns but higher risk. Bonds have lower potential returns but more predictable income. Many investors own both stocks and bonds to balance risk and return. The mix depends on how much risk you are comfortable with and how long you plan to hold the investments.

How to start learning about stocks

If you are new to stocks, start by reading about individual companies you know — their products, their recent news, their financial reports. Most public companies publish quarterly earnings reports and annual reports that explain how they performed and where they are headed. These documents are free and available on company websites.

Many brokers offer educational resources, including articles, videos, and simulators where you can practice buying and selling stocks with fake money. Paper trading (using a simulator) lets you learn how orders work and how prices move without risking real money. You can also follow financial news sites to see how different events affect stock prices and understand the reasoning behind market movements.

Frequently Asked Questions

Can I lose more money than I invested in a stock?

No. If you buy 100 shares at $50 per share, you invest $5,000. If the stock falls to $0, you lose $5,000 — your entire investment. You cannot lose more than you put in because the stock price cannot go below zero. However, losing your entire investment is possible if a company fails.

What time of day should I buy stocks?

The stock market opens at 9:30 a.m. Eastern time and closes at 4 p.m. Eastern time on weekdays. You can place orders anytime during those hours. Some brokers also offer after-hours trading, which happens from 4 p.m. to 8 p.m., though prices can be more volatile and spreads wider. There is no single "best" time to buy — it depends on your strategy and the stock you are watching.

Do I need a lot of money to start buying stocks?

No. Many brokers allow you to open an account with as little as $1 or $0. Some stocks trade for under $10 per share, so you can buy a single share with a small amount of money. However, some brokers have minimum account balances or charge fees, so read the terms before opening an account.

What is a stock split?

A stock split happens when a company divides its existing shares into more shares. For example, a 2-for-1 split means each share becomes two shares, and the price per share is cut in half. Your total ownership percentage stays the same — if you owned 100 shares worth $10,000, after a 2-for-1 split you own 200 shares worth $10,000. The company does this to make shares more affordable for small investors.

Can I buy stocks from other countries?

Yes. Many U.S. brokers allow you to buy stocks listed on foreign exchanges, including Canadian, European, and Asian exchanges. However, you may face currency conversion fees, higher commissions, and different trading hours. Some foreign stocks are also listed on U.S. exchanges as American Depositary Receipts (ADRs), which makes them easier to buy through a regular U.S. brokerage account.