N.C. Gen. Stat. § 105-187.81
A producer must file with the Secretary a bond or an irrevocable letter of credit after obtaining a permit under G.S. 113-395. A bond or an irrevocable letter of credit must be conditioned upon compliance with the requirements of this Article, be payable to the State, and be in the form required by the Secretary. The amount of the bond or irrevocable letter of credit is two times the applicant's average expected monthly tax liability under this Article, as determined by the Secretary, provided the amount of the bond may not be less than two thousand dollars ($2,000) and may not be more than two million dollars ($2,000,000). The Secretary should periodically review the sufficiency of bonds required of producers and increase the amount of a required bond when the amount of the bond furnished no longer covers the anticipated tax liability of the producer and decrease the amount when the Secretary determines that a smaller bond amount will adequately protect the State from loss. When notified to do so by the Secretary, a person who is required to file a bond or an irrevocable letter of credit must file the bond or irrevocable letter of credit in the amount required by the Secretary within 30 days after receiving the notice from the Secretary.
N.C. Gen. Stat. § 105-187.81