how to calculate the financing interest? Financing interest: financing interest = financing amount × (financing interest /36)× actual use days (financing amount = transaction price of financing purchase * number of shares traded+transaction cost); Securities lending fee: securities lending fee = securities lending amount × (securities lending rate /36)× actual use days; Overdue interest: overdue interest = financing amount or securities lending amount × (overdue interest rate /36)× actual overdue days;