Capital precipitation is common in banks and enterprises. It means that in the process of daily capital inflow and outflow, there is always a certain amount of funds in the account, which is relatively stable, so it is called capital precipitation, which is an image statement. Just like the sediment in the river, some have been washed away, and some have just rushed from the upstream, but there is always a part of the river bottom left as sediment. For example, Alipay, because there will be a certain time difference between the inflow and outflow of funds, there will always be some money "left at the bottom of the river".