The Japan 225, or the Nikkei-225 Stock Average, is an index comprised of the leading blue-chip companies listed in the First Section of the Tokyo Stock Exchange. Created in 1949, the Nikkei-225 is the oldest Asian stock index. The stocks are rated according to their price, not market cap, as in most of the indices. The Nikkei is denominated in Japanese Yen and is reviewed yearly in September. It is an underlying asset for futures, options and exchange-traded funds (ETFs).