The Nikkei 225 is a price-weighted index of the 225 top blue-chip Japanese equities traded on the Tokyo stock exchange. It can be considered as the Japanese equivalent to the Dow Industrials Index in the U.S. In fact, the Nikkei was previously known as the Nikkei Dow Jones Stock Average. Some of the company’s whose stocks are included in the Nikkei are Sony, Toyota, and Panasonic. The Nikkei 225 is the oldest stock index in Asia.