Index Fund (Index Fund), as the name suggests, is a fund product that takes a specific index (such as CSI 300, S&P 500, NASDAQ 100, Nikkei 225, etc.) as the underlying index and takes the constituents of the index as the object of investment, and constructs a portfolio to track the performance of the underlying index by purchasing all or part of the constituents of the index. In general, index funds aim to minimize tracking error so that the trend of the portfolio is consistent with the underlying index, in order to achieve roughly the same rate of return as the underlying index.