What Is the Stock Market & How Does It Work?

Stock market basics

Stock markets facilitate the sale and purchase of stocks between individual investors, institutional investors, and companies.

The vast majority of stock trades take place among investors. If you want to buy shares of Microsoft (MSFT +0.17%), you can hit the "buy" button through your broker's website. When you do, you are buying shares that another investor has decided to sell -- not from Microsoft itself. By purchasing shares of a stock, you become an investor in the company.

What is a stock?

Stocks represent an ownership interest in businesses that choose to have their shares available to public investors. These are known as publicly traded companies. You may also hear stocks referred to as equities or equity securities and sometimes just securities.

A share of stock represents an ownership interest in a company. If you buy a share of Apple (AAPL +0.20%), you own a small part of the business and get to share in the company's success.

Instead of being owned by an individual or a private group, some companies (such as Apple) choose to "go public" with an initial public offering (IPO). This means that anyone can become a part-owner by purchasing shares of the company's stock.

How are prices determined on a stock market?

Stock prices on exchanges are governed by supply and demand, plain and simple.

At any given time, there's a maximum price someone is willing to pay for a certain stock, known as the bid price. There's also a minimum price someone else is willing to set for the shares of stock, known as the ask price.

If there is a lot of demand for a stock, investors will buy shares more quickly than sellers want to get rid of them. This can move the price higher. On the other hand, if more investors are selling a stock than buying, the market price will drop.

There are plenty of catalysts that can push the market up or down. For example, a market can fall due to things like inflation pressures, supply chain issues, rising interest rates, and recession fears. These factors resulted in more investors selling stock than buying, leading to more investors selling and possibly even a stock market crash!

Market makers ensure there are always buyers and sellers

A key concept to help understand the stock market is the idea of a market maker.

Think of it this way. There aren't always buyers to match up with sellers of stocks. However, stock trades typically go through in seconds. How can brokers buy and sell stocks in your account instantaneously?

Individuals known as market makers act as intermediaries between buyers and sellers. This ensures there's always a liquid marketplace for stocks on an exchange. With a liquid market like this, investors can choose to buy and sell shares immediately, whenever they want, during market hours. Here's a rundown of what investors should know about the process:

• Market makers buy and hold shares and continually list buy-and-sell quotations for shares.
• The highest offer to buy shares listed from a market maker at any given time is known as the bid. The lowest offered selling price is known as the ask.
• The difference between the two is called the spread.

Because of market makers, you'll never have to wait to sell stocks at their full market value.

What happens when you buy a stock?

Investors must carry out the transactions of buying or selling stocks through a broker. In a nutshell, a broker is simply an entity licensed to trade stocks on a stock exchange.

Throughout most of the stock market's history, a broker has been an actual person whom you tell what to buy and sell. In the modern era, however, it is an online stock broker -- say, Schwab or Fidelity. Firms like these usually process the entire transaction electronically, although most still offer the ability to complete a trade by phone.

When you buy a stock, here's the simplified version of how it works:

1. You tell your broker (or input electronically) what stock you want to buy and how many shares you want.
2. Your broker relays your order to the exchange. A market maker sells you shares at the current market price.
3. The shares are then delivered to your account.

It works the same way when you choose to sell a stock.

How does a stock index track the stock market?

When discussing the stock market, people often generalize "the market" to a stock index. Stock indexes, such as the S&P 500 or the Dow Jones Industrial Average, or DOW for short, are a representation of the performance of a large group of stocks or a particular stock market sector.

These are used as a benchmark to compare the performance of individual stocks or an entire portfolio. For example, the S&P 500 index tracks the performance of 500 of the largest publicly traded companies in the U.S.

It's important to understand that the major stock indexes you see on TV and in the news do not fully represent the entire stock market. It's entirely possible for a stock to decline even if a certain index is up, and vice versa.

The only true way to understand what the stock market is doing is by looking at an average of multiple indices across various sectors.

Stock markets, stock exchanges, and stock indexes

There are three different terms here with similar and often misunderstood meanings:

• Stock market: The process and facilitation of investors buying and selling stocks with one another.
• Stock exchange: The actual intermediary that connects buyers with sellers, such as the New York Stock Exchange (NYSE).
• Stock index: A numerical representation of a group of stocks that is used to track their collective performance. Such as the S&P 500 or Nasdaq Composite.