Every day, millions of investors buy and sell shares in companies listed on the US stock market. From household names in technology and healthcare to consumer brands and financial institutions, the US stock market plays a central role in the global economy.

But how does it actually work? If you're new to investing, understanding how stocks are bought and sold can help you make sense of market news and build a stronger foundation before making investment decisions.

What Is the US Stock Market?

The US stock market is a network of exchanges where investors buy and sell shares of publicly traded companies. When you purchase a stock, you're buying a small ownership stake in a company. As the company's value changes, the value of its shares may also rise or fall.

The stock market helps companies raise money while giving investors the opportunity to participate in their growth.

Why Do Companies List on the Stock Market?

Many companies choose to list their shares publicly to raise capital. The money raised can be used to expand operations, develop new products, hire employees, reduce debt, or fund future growth.

Listing on a stock exchange also allows early investors and employees to sell shares over time while increasing the company's visibility among investors worldwide.

How Does the US Stock Market Work?

The market brings together buyers and sellers. When an investor wants to buy shares, they place an order through a licensed broking platform. Another investor may decide to sell those same shares.

The stock exchange matches these buy and sell orders electronically, allowing trades to occur in seconds. Every completed trade contributes to the market price of a stock, which constantly changes throughout the trading day based on supply and demand.

The Two Major US Stock Exchanges

New York Stock Exchange (NYSE)

The NYSE is the world's largest stock exchange by market capitalization and is home to many established global companies.

Nasdaq

Nasdaq is known for its electronic trading platform and includes many technology-focused companies, although businesses from many industries are listed there.

Both exchanges operate under regulatory oversight and provide investors with access to thousands of publicly traded companies.

Who Participates in the Stock Market?

Several groups play important roles in keeping the market functioning.

• Individual investors - buy and sell shares for personal investment goals
• Institutional investors such as pension funds and mutual funds manage investments on behalf of clients or beneficiaries
• Brokerage firms execute trades for investors
• Market makers - help provide liquidity by continuously quoting buy and sell prices, making it easier for trades to occur efficiently
  

What Makes Stock Prices Change?

Stock prices move constantly as new information becomes available.

Common factors include:

• Company earnings reports
• Economic data
• Inflation
• Interest rate decisions
• Industry developments
• Global events
• Investor sentiment

Because these factors can change quickly, stock prices may rise or fall throughout the trading day.

US Stock Market Trading Hours

The regular US trading session runs from 9:30 AM to 4:00 PM Eastern Time (ET) on business days.

Some brokerage firms also offer pre-market and after-hours trading, although these sessions typically have lower trading volumes and may experience greater price volatility.

The market is closed on weekends and certain US public holidays.

Why the US Stock Market Matters Globally

The US stock market is the largest and most liquid equity market in the world. Many of the world's leading companies are listed in the United States, attracting investors from across the globe. Economic developments in the US, including inflation data, interest rate decisions, and corporate earnings, can influence financial markets internationally.

For investors with exposure to US stocks, understanding how the market operates can provide helpful context for interpreting market news and broader economic trends.

Read Also: What is an ETF? A Beginner's Guide to Exchange Traded Funds

Final Thoughts

The US stock market connects companies seeking capital with investors looking to participate in financial markets.

While the mechanics of trading may seem complex at first, the core concept is straightforward: buyers and sellers meet on regulated exchanges to trade ownership of publicly listed companies.

Whether you're learning about stocks, ETFs, or IPOs, understanding how the US stock market works is an important step toward becoming a more informed investor.