A reinsurance participation plan allows an insurance carrier to provide novel loss participation plans to insureds. The insurance carrier cedes a portion of the risk to a reinsurance company, such as a captive reinsurance company. The captive reinsurance carrier then enters into a contractual agreement with the insured for the participation plan, subject to the appropriate regulations for the primary line of insurance in question. The participation plan may be a non-linear participation plan, such as a curvilinear participation plan, where the non-linearities allow the plan to be offered to smaller companies than would otherwise qualify for more traditional retrospective participation plans, and to provide more advantageous plans to larger companies than they would otherwise be offered. The plans may be offered on a multi-year basis with particular diligence in informed consent for the prospective insured. Plans may be offered to small companies whose loss experience is aggregated and then divided according to relative premium amounts among the small companies such that the aggregate losses have a distribution with skewness comparable to that of a medium sized company.