(1) Every insurer or rating organization shall, before using, file with the commissioner every classifications manual, manual of rules and rates, rating plan, rating schedule, minimum rate, class rate, and rating rule, and every modification of any of the foregoing which it proposes. The insurer need not so file any rate on individually rated risks as described in subdivision (1) of RCW 48.19.030; except that any such specific rate made by a rating organization shall be filed.

(2) Every such filing shall indicate the type and extent of the coverage contemplated and must be accompanied by sufficient information to permit the commissioner to determine whether it meets the requirements of this chapter. An insurer or rating organization shall offer in support of any filing:

(a) The experience or judgment of the insurer or rating organization making the filing;

(b) An exhibit detailing the major elements of operating expense for the types of insurance affected by the filing;

(c) An explanation of how investment income has been taken into account in the proposed rates; and

(d) Any other information which the insurer or rating organization deems relevant.

(3) If an insurer has insufficient loss experience to support its proposed rates, it may submit:

(a) Loss experience for similar exposures of other insurers or of a rating organization; or

(b) A complete and logical explanation of how it has developed its proposed rates, including the insurer's analysis of any relevant information and showing why the proposed rates should be considered to meet the requirements of RCW 48.19.020.

(4) Every such filing shall state its proposed effective date.

(5)(a) A filing made pursuant to this chapter shall be exempt from the provisions of RCW 48.02.120(3). However, the filing and all supporting information accompanying it shall be open to public inspection only after the filing becomes effective, except as provided in (b) of this subsection.

(b) For the purpose of this section, "usage-based insurance" means private passenger automobile coverage that uses data gathered from any recording device as defined in RCW 46.35.010, or a system, or business method that records and preserves data arising from the actual usage of a motor vehicle to determine rates or premiums. Information in a filing of usage-based insurance about the usage-based component of the rate is confidential and must be withheld from public inspection.

(6) Where a filing is required no insurer shall make or issue an insurance contract or policy except in accordance with its filing then in effect, except as is provided by RCW 48.19.090.

Effective date—1989 c 25: See note following RCW 48.18.100.