The Nikkei 225, or , more commonly called the Nikkei or the Nikkei index (), is a stock market index for the Tokyo Stock Exchange (TSE). It has been calculated daily by the Nihon Keizai Shimbun (The Nikkei) newspaper since 1950. It is a price-weighted index, operating in the Japanese Yen (JP¥), and its components are reviewed once a year. The Nikkei measures the performance of 225 large, publicly owned companies in Japan from a wide array of industry sectors. Another major index for the Tokyo Stock Exchange is the Tokyo Stock Price Index (TOPIX). History The Nikkei 225 began to be calculated on , retroactively calculated back to May 16th 1949, when the average price of its component stocks was 176.21 yen. Since January 2010, the index is updated every 15 seconds during trading sessions. The Nikkei 225 Futures, introduced at Singapore Exchange (SGX) in 1986, the Osaka Securities Exchange (OSE) in 1988, Chicago Mercantile Exchange (CME) in 1990, is now an internationally recognized futures index. The Nikkei average has deviated sharply from the textbook model of stock averages, which grow at a steady exponential rate. The average hit its all-time high on 29 December 1989, during the peak of the Japanese asset price bubble, when it reached an intra-day high of 38,957.44, before closing at 38,915.87, having grown sixfold during the decade. Subsequently, it lost nearly all these gains, closing at 7,054.98 on March 10th, 2009 — 81.9% below its peak nearly twenty years earlier. On March 15th 2011, the second working day after the massive earthquake in the northeast part of Japan, the index dropped over 10% to finish at 8605.15, a loss of 1,015 points. The index continued to drop throughout 2011, bottoming out at 8160.01 on November 25th, putting it at its lowest close since March 31st, 2009. The Nikkei fell over 17% in 2011, finishing the year at 8455.35, its lowest year-end closing value in nearly thirty years, when the index finished at 8016.70 in 1982. The Nikkei started 2013 near 10,600, hitting a peak of 15,942 in May. However, shortly afterward, it plunged by almost 10% before rebounding, making it the most volatile stock market index among the developed markets. By 2015, it has reached over 20,000 mark; marking a gain of over 10,000 in two years, making it one of the fastest growing stock market indexes in the world. However, by 2018,