(a) Each service corporation shall set aside into a “surplus fund” an amount of money equal to not less than two percent of all sums hereafter received by it on account of subscriber's contracts, until the surplus fund amounts to not less than $50,000 if a medical service corporation or hospital service corporation, or $100,000 if a combination medical-hospital service corporation.

(b) After the minimum surplus fund is established the service corporation may in like manner increase it to an amount not to exceed the total gross collections from subscribers during the immediately preceding seven months.

(c) That portion of the surplus fund referred to in (a) of this section may be used by the service corporation by express appropriation by action of its board of directors solely if necessary to pay the additional health care costs and expenses under its contracts resulting from disease, epidemic or catastrophic occurrences in which numerous persons were injured in the same occurrence.

(d) If the surplus fund is at any time depleted below the minimum amount required under (a) of this section, the service corporation shall replenish the fund by a resumption or continuance of allocations from subscribers' payments, as provided for original accumulation of the fund under (a) of this section, or by other reasonable means that may be approved by the director.

(e) The director may adopt regulations that are necessary to assure that each service corporation maintains an adequate surplus fund.