The American Stock Exchange (AMEX) was once the third-largest stock exchange in the United States, as measured by trading volume. The exchange, at its height, handled about 10% of all securities traded in the U.S.Today, the AMEX is known as the NYSE American. In 2008, NYSE Euronext acquired the AMEX and has since made it a subsidiary of NYSE Euronext Holdings LLC. In 2013, it rebranded again as NYSE MKT LLC (NYSE Amex Equities). The AMEX is now a small player in today's stock market landscape and primarily focuses on listing small and mid-cap companies