Illinois Statutes Chapter 40. Pensions § 5/20-121. Calculation of proportional retirement annuities

(a) Upon retirement of the employee, a proportional retirement annuity shall be computed by each participating system in which pension credit has been established on the basis of pension credits under each system. The computation shall be in accordance with the formula or method prescribed by each participating system which is in effect at the date of the employee's latest withdrawal from service covered by any of the systems in which he has pension credits which he elects to have considered under this Article. However, the amount of any retirement annuity payable under the self-managed plan established under Section 15-158.2 of this Code or under the defined contribution plan established under Article 2, 14, 15, or 16 of this Code depends solely on the value of the participant's vested account balances and is not subject to any proportional adjustment under this Section.

(a-5) For persons who participate in a defined contribution plan established under Article 2, 14, 15, or 16 of this Code to whom the provisions of this Article apply, the pension credits established under the defined contribution plan may be considered in determining eligibility for or the amount of the defined benefit retirement annuity that is payable by any other participating system.

(b) Combined pension credit under all retirement systems subject to this Article shall be considered in determining whether the minimum qualification has been met and the formula or method of computation which shall be applied, except as may be otherwise provided with respect to vesting in State or employer contributions in a defined contribution plan. If a system has a step-rate formula for calculation of the retirement annuity, pension credits covering previous service which have been established under another system shall be considered in determining which range or ranges of the step-rate formula are to be applicable to the employee.

(c) Interest on pension credit shall continue to accumulate in accordance with the provisions of the law governing the retirement system in which the same has been established during the time an employee is in the service of another employer, on the assumption such employee, for interest purposes for pension credit, is continuing in the service covered by such retirement system.