What Is a Stock Exchange?
Think of a stock exchange like a giant marketplace — except instead of produce, people are buying and selling pieces of companies. The two biggest in the U.S. are the New York Stock Exchange (NYSE) and NASDAQ.
Companies "list" their shares on an exchange so investors can trade them. The exchange provides the infrastructure — the rules, the technology, the record-keeping — that makes millions of trades happen smoothly every day.
When a company wants to list for the first time, they do an IPO (Initial Public Offering) — selling shares to the public to raise money for growth. After that, shares trade between investors. The company doesn't receive money from those secondary trades.
How Prices Are Set
Stock prices aren't set by anyone in charge — they emerge from the constant push and pull of buyers and sellers.
If lots of people want to buy a stock and fewer want to sell, the price goes up. If more people want to sell than buy, the price drops. Every trade represents a buyer and a seller agreeing on a price at that exact moment.
This is why prices move constantly during the trading day. New information — an earnings report, a news headline, a Fed announcement — changes how much people are willing to pay. The market is essentially a real-time auction for company ownership, happening at massive scale.
What People Mean by "The Market"
When someone says "the market was up today," they're usually referring to a major index like the S&P 500, the Dow Jones Industrial Average, or the NASDAQ Composite. These are scoreboards that track groups of stocks.
The S&P 500 tracks 500 large U.S. companies and is the most commonly referenced benchmark. It's important to understand that "the market" going up doesn't mean every stock moved that direction. On a day the S&P 500 rises 1%, some individual stocks may have fallen 5%. The index is an average, weighted by company size.
Market Hours and How Trading Works
U.S. markets are open Monday through Friday, 9:30 AM to 4:00 PM Eastern Time. To buy or sell stocks, you need a brokerage account.
When you place a trade, you submit an order. A "market order" buys or sells immediately at whatever the current price is. A "limit order" only executes if the price reaches a level you specify — useful if you want to buy at a specific price but aren't in a rush.
For most long-term investors buying index funds, a simple market order during regular market hours is perfectly fine.
Bulls, Bears, and Market Cycles
A bull market is a sustained period of rising prices — generally defined as a 20% rise from recent lows. A bear market is the opposite: a sustained decline of 20% or more.
Markets move in cycles. Bull markets tend to last longer than bear markets on average, but bear markets can be sharp and painful. Historically, every bear market has eventually ended and been followed by a recovery.
Knowing this doesn't make bear markets easy to live through emotionally. But it helps you keep perspective when headlines are screaming that everything is falling apart.
Market Makers and Liquidity
Ever wonder how there's always someone to buy or sell from when you place a trade? That's partly thanks to market makers — firms that stand ready to buy and sell securities, profiting from the small difference between the buy and sell price (called the "spread").
This creates liquidity — the ability to convert your investment to cash quickly. Highly liquid investments like large-cap stocks and major ETFs can be bought or sold almost instantly. Less liquid investments may take more time and cost more to trade.
Liquidity matters most when you need your money urgently — one more reason beginners are often steered toward large, liquid index funds.
1. What determines a stock's price?
2. When someone says 'the market was up 1% today,' what are they usually referring to?