The Sensex, short for the Bombay Stock Exchange Sensitive Index, is a stock market index that tracks the performance of 30 large and well-established companies listed on the Bombay Stock Exchange. It serves as a benchmark for the overall health of the Indian stock market and reflects the economic performance of the country. Investors and analysts use the Sensex to gauge market trends and make informed investment decisions. The index is calculated based on the free-float market capitalization of its constituent companies, which means it considers only the shares available for trading, excluding locked-in shares held by promoters or government.