A stock exchange is a regulated marketplace where buyers and sellers trade securities such as stocks, bonds, and derivatives. Major stock exchanges include the New York Stock Exchange (NYSE), NASDAQ, London Stock Exchange (LSE), Tokyo Stock Exchange (JPX), and Hong Kong Stock Exchange (HKEX). Each exchange has specific trading hours, listing requirements, and regulatory frameworks. The world has over 60 major stock exchanges across all continents. The NYSE is the largest by market capitalization at approximately $25 trillion, followed by NASDAQ at about $22 trillion. Exchanges provide price transparency, liquidity, and regulatory oversight that make organized securities trading possible. Modern exchanges are primarily electronic, matching buy and sell orders through automated systems in milliseconds, though some like the NYSE maintain a physical trading floor alongside electronic systems.