Haw. Rev. Stat. § 435E-2: Cooperative indemnity.

Physicians and surgeons may, any other law to the contrary notwithstanding, form cooperative corporations for the purposes of this chapter. The members of a cooperative corporation, which shall be limited to physicians and surgeons only, may enter into unincorporated interindemnity or reciprocal contracts among themselves; provided that such contracts indemnify solely in respect to medical malpractice claims against such members, and do not collect in advance of loss any moneys other than contributions by each member to a collective reserve trust fund or for necessary expenses of administration. In addition, each such interindemnity, reciprocal, or interinsurance contract shall meet the requirements of this chapter.