Provided, however,
The bond shall be in such reasonable form and amount as a majority of the board of directors of the registered management investment company who are not interested persons of such investment company as defined by section 2(a)(19) of the Act shall approve as often as their fiduciary duties require, but not less than once every twelve months, with due consideration to all relevant factors including, but not limited to, the value of the aggregate assets of the registered management investment company to which any covered person may have access, the type and terms of the arrangements made for the custody and safekeeping of such assets, and the nature of the securities in the company's portfolio: Provided, however, That (1) the amount of a single insured bond shall be at least equal to an amount computed in accordance with the following schedule: