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How the stock market works, explained in plain English

The stock market sounds huge and mysterious. Underneath, it's a very large, very fast place where people agree on a price. Once you see the 5 moving parts, the news and the charts start to make sense.

Beginner guide · 8-minute read · Updated 2026-10-21

A share is a small piece of a company

Start with one company. Say it is worth $1 billion, and it's split into 100 million equal pieces. Each piece is a share, worth about $10.

Own one share and you own a tiny slice of that company. If the company grows, more people want that slice. If it struggles, fewer do.

Why do companies sell shares at all? To raise money. When a company first sells shares to the public, that's called an IPO (initial public offering). After that, the shares trade between investors, not with the company.

The market is a meeting place

Most stock trading happens on exchanges, like the New York Stock Exchange (NYSE) and Nasdaq. Think of an exchange as a giant, electronic auction room.

Buyers say what they'll pay. Sellers say what they'll take. When a buyer and a seller agree, a trade happens, and that becomes the latest price.

That's all a stock price is: the last price two people agreed on. Nobody "sets" it. It moves every time buyers and sellers shift what they'll accept.

Bid, ask and the gap between them

At any moment, a stock has two prices:

• Bid: the highest price a buyer is offering right now.
• Ask: the lowest price a seller will accept right now.

The small gap between them is the Spread. Busy stocks have tiny spreads, often a cent. Quiet stocks can have wide ones. More on this in our Bid and ask definition.

How your order actually gets filled

You don't phone the exchange. You use a broker, an app or website that sends your order to the market for you.

The two order types every beginner should know:

• Market order: "Buy now at the best price available." Fast, but the price can be a little worse than you saw.
• Limit order: "Buy only at this price or better." You control the price, but it may not fill.

We compare them side by side in market vs limit order.

Why prices move

Here's the short version. Price moves when one side is more eager than the other.

More eager buyers than sellers? They have to pay up, so price rises. More eager sellers? They have to accept less, so price falls.

What makes people eager? Company results, interest rates, news, and plain crowd mood. We go through the big ones in what moves stock prices.

Market hours

The regular US session for NYSE and Nasdaq runs 9:30 am to 4:00 pm Eastern Time, Monday to Friday. Many brokers also offer pre-market and after-hours trading. Those sessions are usually quieter, with wider spreads.

The exchanges close on certain holidays. Our market hours tool shows what's open right now in your own time zone.

Indexes: the market's scoreboard

When the news says "the market was up today," it usually means an index. An Index is a basket of stocks tracked as one number.

You can't buy an index directly. But you can buy an ETF, a fund that trades like one stock and holds the whole basket.

Investing vs trading

Both happen in the same market. The difference is time and intent.

• Investing: buy shares of companies and hold them for years.
• Trading: buy and sell over days, hours or minutes, aiming to catch a price move.

Traders can also take a trade that gains if price falls, by selling first. That's called going short. See Long and short for how that works. Either way, every trade can lose money, which is why traders decide their exit before they get in.

Who keeps it fair

In the US, the SEC (Securities and Exchange Commission) writes and enforces the main rules. FINRA oversees brokers. Before you open an account, you can look up any broker on FINRA's free BrokerCheck site.

When you sell a stock in the US, the trade settles (the cash and shares officially swap) one business day later. That's called T+1.

One more change worth knowing: the old $25,000 "pattern day trader" minimum for day trading in a margin account was eliminated in 2026. Our PDT rule page explains what changed.

Putting it together: one trade, start to finish

Here's how it all connects, as a simple example:

1. You see a stock at a bid of $49.99 and an ask of $50.00.
2. You place a limit order to buy 10 shares at $50.00.
3. Your broker sends it to the market. A seller at $50.00 matches it.
4. You now own 10 shares. One business day later, the trade settles.
5. Later, you place an order to sell. Whatever price you get decides your result, up or down.

Try it today

1. Pick one large company you know.
2. Find its bid, ask and spread.
3. Look up which index it belongs to.
4. Open its daily chart and read it with our stock chart guide.

Questions