N.M. Admin. Code § 1.6.5.8
Certificates of coverage shall be issued on an annual basis, unless otherwise determined by the director, on or before July 1 of the state fiscal year, and in the sole discretion of the director shall be in force on July 1 of that fiscal year, or as soon as practicable thereafter, and shall remain in effect for a period of one year from the date of issuance or until superceded by another certificate of coverage, unless otherwise earlier terminated in writing by the director. The director shall issue certificates of coverage by a letter of administration issued to a governmental entity attaching the certificates of coverage. The letter of administration will describe the type, extent, nature and description of coverage(s), and may also include other matters and administrative procedures reasonably necessary and which must be followed to carry on or administer the requirements of the Tort Claims Act.
N.M. Admin. Code § 1.6.5.8