Stock exchanges are an institutionalized exchange place where individual participants perform transactions in securities for the purpose of gaining profit. Given the complexity of the concept of stock exchange, the theoretical part of the paper defines financial markets and securities. The financial market can be most generally defined as the place where the supply and demand of financial assets meet. One of the basic divisions of financial markets is the division into money markets and capital markets. Stock exchanges belong to the capital markets and are considered the most attractive places for conducting financial transactions. Participants in stock exchanges are stock exchange sellers who are willing to sell securities at an appropriate price, stock exchange investors who intend to invest their funds with the intention of buying securities, and intermediaries who appear in the event of an indirect transfer of funds. Securities are divided into equity and debt securities, i.e. shares and bonds. Shares represent variable yield securities while bonds represent fixed income securities. When mentioning stocks, the term stock exchange indices is often related. Stock exchange indices represent sets of securities and are used to estimate the movement of stock exchange activities. The research part of the paper analyzes the Nasdaq, Euronext and Japan Exchange Group considering market capitalization, number of listed companies, price movements of selected shares and stock exchange indices in the period from 1.1.2016. to 1.1.2021. The research showed that the Nasdaq and the observed stock exchange indice Nasdaq 100 have the highest market capitalization and the highest values of stock exchange indices. The achieved research results will be presented graphically and tabularly, and the reasons of their occurrence will be stated, such as the impact of the COVID-19 pandemic on market movements.