Fully replicated index fund: strive to allocate according to the composition and weight of benchmark index, with the goal of minimizing tracking error. Enhanced index fund: On the basis of allocating most assets according to the weight of benchmark index, some assets are also used for active investment. Its goal is to get higher income than the benchmark index while closely tracking the benchmark index. The income of index funds comes from the price fluctuation and dividends of investment targets, which is reflected in the fluctuation of index funds' own net value. The income calculation formula of index funds is the same as that of general funds, which mainly depends on the net value of index funds at the time of subscription/redemption, dividend distribution and various fund fees charged at the time of subscription/redemption. Calculation formula of index fund income: share = investment ×( 1+ subscription rate) ÷ net value on the day of subscription+interest income = net value on the day of redemption × share ×( 1- redemption rate)+dividend-investment index fund type: closed-end index fund. Can be traded in the secondary market, can not purchase, redemption. Ordinary open index funds. You can't trade in the secondary market, but you can purchase and redeem it. Index ETF fund. ETF can not only be traded in the secondary market, but also be purchased and redeemed. Index LOF fund. LOF can be traded in the secondary market, and can also be purchased and redeemed.