The stock market is a network of exchanges, brokers, investors and other market participants through which shares of publicly traded companies are bought and sold. A stock represents an ownership interest in a company, although the rights attached to shares vary by security.
From company ownership to public trading
Companies may issue shares to raise capital. After shares begin trading publicly, investors can generally buy and sell them in the secondary market through brokerage accounts. Major U.S. exchanges provide organized marketplaces where orders are matched.
Why stock prices change
Stock prices respond to supply and demand. Company earnings, expectations about future growth, interest rates, economic conditions, industry developments, news and investor sentiment can all influence what buyers are willing to pay and sellers are willing to accept.
Market orders and limit orders
A market order generally seeks execution promptly at the best available price, but the exact price is not guaranteed. A limit order specifies the maximum price a buyer will pay or the minimum price a seller will accept; execution is not guaranteed.
Indexes are measurements, not the whole market
Indexes such as the S&P 500 or Dow Jones Industrial Average track selected groups of securities and are often used as market benchmarks. An index level is a measurement; investors generally obtain index exposure through products such as index mutual funds or ETFs rather than buying the index itself.
What beginners should remember
Owning a stock can provide growth potential, but a company’s share price can fall substantially and individual companies can fail. Research, diversification, a long-term perspective and awareness of costs can help investors make more informed decisions.
Educational note: This article is for general educational purposes and does not provide individualized investment, tax, or legal advice. Investing involves risk, including possible loss of principal.
Article information
Published: September 6, 2026 Updated: September 6, 2026
Reviewed by: Allocate Yourself Editorial Team Last reviewed: 2026-09-06
