NYSE' The NYSE (New York Stock Exchange) is a major stock exchange located in New York City. It is the largest stock exchange in the world by market capitalization and is the oldest stock exchange in the United States. The NYSE Acquisition is a term used to describe the acquisition of the NYSE by the American Stock Exchange (AMEX) in 2008. The AMEX is a stock exchange based in New York City that was founded in 1842. The acquisition of the NYSE by the AMEX was a major event in the history of the stock market, as it created the first transatlantic stock exchange.