(1) No insurer shall increase the premium unilaterally or decrease the coverage benefits on renewal of a policy of insurance that provides coverages on commercial exposures such as general comprehensive liability, municipal liability, automobile liability and physical damage, fidelity and surety, fire and allied lines, inland marine, errors and omissions, excess liability, products liability, police liability, professional liability, or false arrest insurance unless the insurer mails by first-class mail to the named insured, at the last address shown in the insurer's records, at least forty-five days in advance a notice, accompanied by the reasons therefor, stating the renewal terms and the amount of premium due. If the insurer fails to furnish the renewal terms and the statement of the amount of premium due at least forty-five days prior to the expiration date of the policy, the insurer shall automatically extend the existing policy for a period of forty-five days and the premium for this extended period shall be prorated based on the premium applicable to the existing policy. If the insurer fails to meet the requirements of this section prior to the expiration date of the existing policy, the insurer shall be deemed to have renewed the insured's policy for an identical policy period at the same terms, conditions, and premium as the existing policy.

(2) A notice of a decrease in coverage benefits during the term of a policy of insurance identified in subsection (1) of this section shall be valid only if it sets forth the reason for the decrease and is based on one or more of the following reasons:

(a) Nonpayment of premium;

(b) A false statement knowingly made by the insured on the application for insurance;

(c) A substantial change in the exposure or risk other than that indicated in the application and underwritten as of the effective date of the policy unless the insured has notified the insurer of the change and the insurer accepts such change.

(3) This section shall not apply to insurance companies authorized to write surplus line insurance in Colorado.