(1) Any domestic stock insurer may, if its charter so provides, issue policies entitled to participate from time to time in the earnings of the insurer through dividends.

(2) Any classification of its participating policies and of risks assumed thereunder which the insurer may make shall be reasonable. No dividend shall be paid which is inequitable or which unfairly discriminates as between such classifications or as between policies within the same classification.

(3) No such insurer shall issue in this state both participating and nonparticipating policies for the same class of risks; except, that both participating and nonparticipating life insurance policies may be issued if the right or absence of the right to participate is reasonably related to the premium charged.

(4) Dividends to participating life insurance policies issued by such insurer shall be paid only out of its surplus funds as defined in subsection (5) of RCW 48.08.030. Dividends to participating policies for other kinds of insurance shall be paid only out of that part of such surplus funds which is derived from any realized net profits from the insurer's business.

(5) No dividend, otherwise earned, shall be made contingent upon the payment of renewal premium on any policy.