In an economy, some individuals/ institutions have an idle cash surplus, while some have a cash deficit and are struggling to raise funds, which is where capital markets step in.
Capital markets are financial markets where the trade of different financial assets takes place. It is a channel for buyers and sellers to trade bonds, stocks, currencies, etc. Capital markets provide the opportunity to deploy idle savings of individuals and institutions. They provide access to market participants for raising funds and are closely linked with the development of an economy.