Mont. Code § 33-23-301
Whenever an action for damages is filed against or a claim or demand for damages is made to an insurer of a physician and surgeon, dentist, registered nurse, nursing home administrator, licensed physical therapist, podiatrist, psychologist, osteopath, chiropractor, pharmacist, optometrist, or veterinarian, duly licensed as such under the laws of this state, or against a licensed hospital or long-term care facility as the employer of any such person, in an action, claim, or demand for error, omission, professional negligence, or performance of services without consent, and such action, claim, or demand is later determined to be unfounded and no payment is made by the insurer to the claimant on behalf of such licensee or licensed hospital or long-term care facility or is finally determined to establish nonliability to plaintiff by such licensee or licensed hospital or long-term care facility, the fact of such litigation, claim, or demand shall not be a ground for cancellation or for any increase in insurance premium rates of the professional liability insurance during the term of the policy.
§ 33-23-301, MCA