Glossary · Stocks and markets
Stock exchange
A stock exchange is a marketplace with strict rules where shares of listed companies are bought and sold, such as the New York Stock Exchange or Nasdaq.
Also called: exchange, bourse, NYSE, listing venue
United States, end of 2025: all its exchanges’ listed companies. Then China and Japan.
In plain words
An auction house sells paintings; a stock exchange sells pieces of companies, millions of times a day. Buyers say how much they will pay, sellers say how much they want, and the exchange’s computers match them in a fraction of a second.
Only companies that meet the exchange’s rules are listed there: they must publish audited accounts, report important news promptly and have enough shares in public hands. In return, their shares get a public price and millions of possible buyers.
The two giants are in New York: the New York Stock Exchange, which traces its start to a 1792 agreement signed under a buttonwood tree on Wall Street, and Nasdaq, the first electronic stock market, opened in 1971. Other big ones are in Shanghai, Shenzhen, Tokyo, Hong Kong, Mumbai and London.
Example
One trade, step by step
- Sellers are asking $50.01, $50.02 and $50.03 for a share; buyers are bidding $49.98, $49.97 and $49.96. The best bid and the best ask are 3 cents apart: that gap is the spread.
- You send a market order to buy 100 shares, “at the best price now”. It is matched with the seller asking $50.01: you pay $5,001.
- Had you sent a limit order to buy at $50.00, you would wait in line until a seller accepted $50.00, which might never happen.
- The trade settles the next business day (the US rule since May 2024): the shares move to your account and the cash to the seller.
The price of the last trade is the “stock price” you see quoted.
One level deeper
Exchanges earn money from trading fees, listing fees and selling their price data. Behind every trade, a clearing house stands between buyer and seller, so that if one side fails, the other is still paid. Market makers keep offering to buy and to sell, earning the spread in return for always being ready to trade.
Most trading today is electronic. In the United States it is spread over more than a dozen exchanges and many private trading systems, linked so that an order goes to the best available price. The NYSE trading floor still exists, mostly for the opening and closing auctions and for television.
A company joins an exchange by selling shares to the public in an IPO (or by listing its existing shares directly). If it later breaks the rules, for example by letting its share price stay below $1 for too long on the NYSE or Nasdaq, it can be delisted.
The largest stock markets in the world
The value of the companies listed on each country’s exchanges at the end of 2025, in US dollars. A country’s exchanges are added together: in the United States mainly the NYSE and Nasdaq, in China the Shanghai and Shenzhen exchanges; Hong Kong is counted separately.
The numbers behind the chart
| 2025 | |
|---|---|
| United States | $68.9T |
| China | $15.5T |
| Japan | $7.61T |
| Hong Kong | $6.09T |
| Canada | $4.62T |
| Germany | $2.9T |
| South Korea | $2.76T |
| Switzerland | $2.51T |
| Saudi Arabia | $2.36T |
| Australia | $2.05T |
Why it matters
Exchanges turn the ownership of a company into something you can sell in seconds. That ease of selling is a big part of why people are willing to invest at all.
Their listing rules force companies to publish their numbers, so investors (and websites like this one) can see how they are doing.
An open, public price helps everyone: companies learn what investors think they are worth, and small savers trade at the same prices as professionals.
A common mistake
Myth: When I buy a share on the exchange, my money goes to the company.
In fact: Only when the company sells new shares, as in an IPO. On an ordinary day the exchange matches you with another investor who is selling; the company is not part of the trade.
Questions people ask
What is the largest stock exchange in the world?
The two largest are both in New York: the New York Stock Exchange and Nasdaq. Together, the companies listed in the US were worth $68.9T at the end of 2025.
What is the difference between the NYSE and Nasdaq?
The NYSE is the older one and still keeps a trading floor; Nasdaq was electronic from the start and became the home of many technology companies. For an investor, buying a share works the same way on either.
Are stock exchanges open on weekends?
No. Stock exchanges trade on weekdays and close on public holidays; US exchanges are open from 9:30 am to 4 pm Eastern Time. Crypto exchanges, by contrast, never close.
Read more on BigCapital
About the numbers
- The numbers on this page are recalculated from the data every night; the sources are listed at the end of the page.
- Stock market capitalization (listed domestic companies): The World Bank: World Development Indicators: Market capitalization of listed domestic companies (current US$) (CM.MKT.LCAP.CD). Original source: World Federation of Exchanges database, World Federation of Exchanges (WFE).
- India is left out of the 2025 ranking: the World Bank puts its market at $10.6T, about twice what its exchanges themselves reported, apparently because companies listed on both of its big exchanges are counted twice.
- This page explains a term. It is not investment advice.