Mont. Code Ann. § 39-51-1102

An employing unit not otherwise subject to this chapter or any employing unit for which services are performed that do not constitute employment as defined in this chapter may file with the department a written election that all such services performed by individuals in its employ in one or more distinct establishments or places of business shall be deemed to constitute employment for all purposes of this chapter for not less than 2 calendar years. Upon the written approval of such election by the department, such services shall be deemed to constitute employment subject to this chapter from and after the date stated in such approval. Such services shall cease to be deemed employment subject hereto as of January 1 of any calendar year subsequent to such 2 calendar years only if at least 30 days prior to such January 1 such employing unit has filed with the department a written notice to that effect.