The NIKKEI 225 Stock Average is a measure of share values on the Tokyo Stock Exchange. It is the simple average of the price of its 225 components with an adjustment made to take account of stock splits.

Japan's most widely-quoted equity index. The Nikkei 225 is a price-weighted index calculated by leading financial information company Nihon Keizai Shimbun on the 225 largest stocks in the first section of the Tokyo Stock Exchange.

The major Japanese share index listing the top 225 leading stocks traded on the Tokyo Stock Exchange.