Open-end fund transactions are divided into on-site transactions and off-site transactions. What is bought in a bank fund company is an over-the-counter transaction, and the purchase and redemption price is subject to the unit net value announced by the fund company, that is, the net value announced by each fund network. However, the trading in the stock market (as seen in the stock software) belongs to on-site trading, and the price fluctuates, which is not the real net value exactly. Once the closing price is inconsistent with the net value announced on the same day, it is called premium, which is very common.