Each licensee under this part must at all times possess permissible investments having an aggregate market value, calculated in accordance with generally accepted accounting principles, of not less than the aggregate face amount of all outstanding payment instruments issued or sold by the licensee in the United States. This requirement may be waived by the commissioner if the dollar volume of a licensee's outstanding payment instruments does not exceed the bond or other security devices posted by the licensee pursuant to § 45-7-208.