Mont. Code Ann. § 70-20-314

When real property is occupied by a tenant, a grant of any estate in the property by the tenant's landlord is valid without an agreement to continue the tenancy by the tenant to the grantee. However, the payment of rent to the grantor by the tenant before notice of the grant is binding upon the grantee, and the tenant is not liable to the grantee for any breach of the condition of the lease until the tenant has had notice of the grant.