Before the opening of the HKEx, China will calculate the exchange rate provided by the exchange banks and release it to the market through the website of the Shanghai Stock Exchange. The reference exchange rate includes two items: the reference price for buying Hong Kong dollars and the reference price for selling Hong Kong dollars. Domestic securities companies can use the reference exchange rate to control investors' funds. That is, when investors buy Hong Kong stocks, securities companies will use the selling price of Hong Kong dollars to calculate the RMB funds that investors need to pay; When investors sell Hong Kong stocks, securities companies will use the reference price of Hong Kong dollars to calculate the RMB funds that investors can obtain. The idea of calculating the exchange rate is that after the daily closing, China will calculate the net amount (unilateral, net amount receivable or net amount payable) according to the stock exchange situation of Hong Kong stocks in the whole market. After the exchange with the foreign exchange bank in Hong Kong, the exchange cost will be evenly distributed to the exchange rate calculated according to all the buying and selling transactions on that day, which is applicable to the RMB and fund settlement office of the investor on that day. The settlement exchange rate includes the buying settlement exchange rate and the selling settlement exchange rate.