(a) Each group hospital service corporation shall maintain reserves sufficient to cover liability for claims incurred but not yet paid and the expenses incurred in settling those claims.
(b) A group hospital service corporation shall estimate the amount necessary to satisfy the reserve requirements using a method submitted to the commissioner for approval. The estimate method used by the corporation is considered approved on the 30th day after the date filed with the commissioner unless the commissioner affirmatively approves or disapproves the method before that date.