N.H. Rev. Stat. Ann. § 286:4-a

The selectmen of any town or the licensing committee of any city shall determine whether the fee for the license prescribed herein will for each event licensed hereunder be adequate to reimburse the town or city for the extra expense in protecting the health and safety of the public which can reasonably be attributed to the event to be licensed. When the license fee is found to be inadequate, the promoter of the event shall agree to put in writing to reimburse the town for the amount of such expense in excess of the license fee and shall furnish a bond for the payment of such amount in a form acceptable to the licensing committee or selectmen.