The MSCI Emerging Markets Index is a stock market index that tracks the performance of large and mid-cap companies in 24 emerging markets, including Brazil, China, India, Mexico, Russia, and South Africa. The index is designed to measure the performance of the emerging markets sector of the global equity market. It is a free float-adjusted market capitalization index, which means that the weight of each company in the index is based on the total market value of its outstanding shares.