5 C.F.R. § 842.604

(a) An unmarried employee or Member retiring under FERS may elect a fully reduced annuity or a one-half reduced annuity to provide a former spouse annuity or annuities.

(b) A married employee or Member retiring under FERS may elect a fully reduced annuity or a one-half reduced annuity to provide a former spouse annuity or annuities instead of a fully reduced annuity to provide a current spouse annuity, if the current spouse consents to the election in accordance with § 842.606 or spousal consent is waived in accordance with § 842.607.

(c) An election under paragraph (a) or (b) of this section is void to the extent that it—

(1) Conflicts with a qualifying court order; or

(2) Would cause the total of current spouse annuities and former spouse annuities payable based on the employee's or Member's service to exceed the maximum amount of survivor annuity that the employee or Member is entitled to provide under § 842.613.

(d) Any reduction in an annuity to provide a former spouse annuity will terminate on the first day of the month after the former spouse remarries before age 55 or dies, or the former spouse's eligibility for a former spouse annuity terminates under the terms of a qualifying court order, unless—

(1) The retiree elects, within 2 years after the former spouse's death or remarriage, to continue the reduction to provide a former spouse annuity for another former spouse, or to provide a current spouse annuity; or

(2) A qualifying court order requires the retiree to provide another former spouse annuity.

(e) Except as provided in § 842.614, the amount of the reduction to provide a former spouse annuity equals—

(1) Ten percent of the employee's or Member's annuity if the employee or Member elects a fully reduced annuity; or

(2) Five percent of the employee's or Member's annuity if the employee or Member elects a one-half reduced annuity.