How Stock Markets Work
BLUF: Stock markets are platforms where shares of publicly-traded companies are bought and sold, with prices determined by supply and demand reflecting investors' expectations of future performance.
Stock markets enable companies to raise capital while giving investors ownership stakes and potential returns.
What are stock markets?
Stock markets (exchanges) facilitate buying and selling of company shares. Major exchanges include NYSE (New York Stock Exchange), NASDAQ, London Stock Exchange, and Tokyo Stock Exchange. When a company goes public (IPO - Initial Public Offering), it sells shares to investors, raising capital for growth. Investors who buy shares become partial owners, entitled to dividends (profit distributions) and voting rights. Share prices fluctuate based on supply and demand—if more people want to buy than sell, prices rise. Trading happens electronically via brokers and market makers who ensure liquidity. Indices (S&P 500, Dow Jones, NASDAQ Composite) track overall market performance by measuring baskets of stocks.
Why stock markets matter
Stock markets allocate capital efficiently—well-performing companies attract investment, poorly-performing ones don't. They enable retirement savings and wealth building for millions through 401(k)s and IRAs. They provide liquidity—shareholders can sell quickly unlike private company owners. Market performance influences consumer confidence and economic policy. However, markets can be irrational—bubbles form when speculation outpaces fundamentals, crashes wipe out wealth suddenly. Short-term thinking may prioritize quarterly earnings over long-term strategy. Insider trading and market manipulation are concerns. Volatility can be extreme—the 2020 COVID crash saw the fastest 30% decline in history, followed by a swift recovery. Correlation across assets means diversification sometimes fails during crises.
How trading works
You place orders through brokers—market orders execute immediately at current prices, limit orders specify maximum buy or minimum sell prices. Order books match buyers and sellers. Market makers facilitate trades by maintaining inventory and quoting bid (buy) and ask (sell) prices—they profit from the spread. High-frequency trading uses algorithms executing millions of trades per second, exploiting tiny price differences. Settlement takes 2 days (T+2) to finalize ownership transfer. After-hours trading happens outside regular hours (9:30am-4pm ET) with less liquidity. Short selling borrows shares to sell, betting on price declines—you profit if prices fall but face unlimited loss potential if prices rise.
Common misconceptions
Myth: Markets are rigged against small investors. Reality: While institutional advantages exist, long-term investing is accessible and profitable for individuals. Myth: You need lots of money. Reality: Fractional shares allow investing small amounts. Myth: You can time the market. Reality: Consistent timing is nearly impossible; time in market beats timing the market. Myth: Stock prices reflect company value perfectly. Reality: Sentiment, speculation, and momentum cause deviations. Myth: The market is zero-sum. Reality: Economic growth means collective gains over time, not just wealth transfers. Myth: Past performance predicts future returns. Reality: Correlation is weak; each period faces unique conditions.