As a basic asset, stock is not a tangible commodity, so there is no storage cost. But its holding cost also has two components: one is the occupation cost, which can be measured according to the market interest rate; The other is the possible stock dividends during the shareholding period. However, since this is the income from holding assets, when it is regarded as a cost, it can only be a negative cost. The net holding cost can be obtained by subtracting the last item from the previous paragraph.