N.D. Cent. Code § 39-16-09
The security required under this chapter must be in such form and amount as the director may require but in no case in excess of the limits specified in section 39-16-05 in reference to the acceptable limits of a policy or bond. The person depositing security shall specify in writing the person in whose behalf the deposit is made, and at any time while such deposit is in the custody of the director or state treasurer, the person depositing it may in writing amend the specification of the person on whose behalf the deposit is made to include an additional person; provided, that a single deposit of security shall be applicable only on behalf of a person required to furnish security because of the same accident. The director may reduce or increase the amount of security ordered in any case if, in the director's judgment, the amount ordered is excessive or inadequate. In case the security originally ordered has been deposited, the excess deposited over the reduced amount must be returned to the depositor or the depositor's personal representative forthwith, notwithstanding the provisions of section 39-16-10.
N.D.C.C. § 39-16-09