The MSCI World Index is a stock market index that measures the performance of large and mid-cap companies across 23 developed countries. It includes over 1,600 stocks, providing a broad representation of the global equity market. Investors use this index to gauge the overall health of the stock market and to compare the performance of individual investments. This index is maintained by MSCI Inc., a leading provider of investment decision support tools. The MSCI World Index is often used as a benchmark for mutual funds and exchange-traded funds (ETFs) that focus on global equities, helping investors understand how their investments are performing relative to the broader market.