A stock market is a global marketplace where investors buy and sell shares, representing ownership claims on businesses. The market has exploded in size, growing from $2.5 trillion in 1980 to $111 trillion by 2023, with the United States dominating at about 59.9% of global market capitalization as of January 2022. Trades are facilitated by stock exchanges like the physical New York Stock Exchange (NYSE) or the electronic NASDAQ, which provide liquidity, real-time pricing, and price discovery. A transaction occurs when a buyer's bid price matches a seller's ask price, and participants range from individual investors to massive institutions like banks, pension funds, and hedge funds. Globally, there are 60 stock exchanges, with just 16 of them—each holding over $1 trillion in market cap—accounting for 87% of the world's total market value.