(a) The Office of Personnel Management shall arrange with a company issuing a policy under this chapter for the reinsurance, under conditions approved by the Office, of portions of the total amount of insurance under the policy, determined under this section, with other life insurance companies which elect to participate in the reinsurance.

(b) The Office shall determine for and in advance of a policy year which companies are eligible to participate as reinsurers and the amount of insurance under a policy which is to be allocated to the issuing company and to reinsurers. The Office shall make this determination at least every 3 years and when a participating company withdraws.

(c) The Office shall establish a formula under which the amount of insurance retained by an issuing company after ceding reinsurance, and the amount of reinsurance ceded to each reinsurer, is in proportion to the total amount of each company's group life insurance, excluding insurance purchased under this chapter, in force in the United States on the determination date, which is the most recent December 31 for which information is available to the Office. In determining the proportions, the portion of a company's group life insurance in force on the determination date in excess of $100,000,000 shall be reduced by—

(1) 25 percent of the first $100,000,000 of the excess;

(2) 50 percent of the second $100,000,000 of the excess;

(3) 75 percent of the third $100,000,000 of the excess; and

(4) 95 percent of the remaining excess.

However, the amount retained by or ceded to a company may not exceed 25 percent of the amount of the company's total life insurance in force in the United States on the determination date.

(d) A fraternal benefit association which is—

(1) licensed to transact life insurance under the laws of a State or the District of Columbia; and

(2) engaged in issuing insurance certificates on the lives of employees of the United States exclusively;

is eligible to act as a reinsuring company and may be allocated an amount of reinsurance equal to 25 percent of its total life insurance in force on employees of the United States on the determination date named by subsection (c) of this section.

(e) An issuing company or reinsurer is entitled, as a minimum, to be allocated an amount of insurance under the policy equal to any reduction from December 31, 1953, to the determination date, in the amount of the company's group life insurance under policies issued to associations of employees of the United States. However, any increase under this subsection in the amount allocated is reduced by the amount in force on the determination date of any policy covering life insurance agreements assumed by the Office.

(f) The Office may modify the computations under this section as necessary to carry out the intent of this section.