The Nikkei 225 is a stock market index that represents 225 of the largest and most actively traded companies listed on the Tokyo Stock Exchange in Japan. It is a key indicator of the Japanese economy and is often used by investors to gauge market performance. The index is calculated using a price-weighted method, meaning that companies with higher stock prices have a greater influence on the index's movements. Established in 1950, the Nikkei 225 includes well-known companies from various sectors, such as technology, automotive, and finance. Some prominent members of the index are Toyota, Sony, and Honda. Investors and analysts closely monitor the Nikkei 225 for insights into market trends and economic health in Japan.