NIKKEI is one of Japan's most influential indexes and is generally used for assessing the economic situation in the country. NIKKEI is one of the indices-centenarians due to historical and economic events; the first publication was in September 1950. Traditionally, NIKKEI includes 225 shares of companies that are most significant in terms of traded value. The main requirement for being included in the index: a company should be listed on the Tokyo Stock Exchange. The list of member companies is reviewed at least once a year, although, from time to time, it occurs less often due to various circumstances.