40 ILCS 5/6-197
The following amounts shall be credited to this reserve: (1) amounts transferred from the city contribution reserve and from the salary deduction reserve for the payment of annuities which have been fixed; (2) amounts deducted from the salary of a fireman after the amount of his age and service annuity has been fixed; and (3) amounts transferred to this reserve from the investment and interest reserve.
All age and service annuities and all widow's annuities shall be charged to this reserve. Any amount to be refunded on account of such annuities under Sections 6-143, 6-160 and 6-162 of this Article shall be charged to this reserve.
If a fireman whose annuity is fixed or granted withdraws from service and thereafter re-enters service before age 63, an amount determined in accordance with this Article shall be charged to this reserve and credited to him for age and service annuity in the city contribution and salary deduction reserves, respectively. Such amount shall be credited in said reserves in the ratio in which the respective amounts transferred from such reserves for age and service annuity for the fireman bear to each other at the time his annuity was fixed. If the wife of such fireman when he re-enters service was his wife when annuity for his wife was fixed, an amount to be determined as provided in this Article shall be transferred from this reserve and credited to the fireman for widow's annuity in the city contribution reserve and the salary deduction reserve, respectively. Such amount shall be credited in said reserves in the ratio in which the respective amounts transferred bear to each other at the time the annuity for the wife of the fireman was fixed.
If at the end of any year the balance in the Annuity Payment Reserve is in excess of the liabilities chargeable thereto by 15% thereof, the excess shall be transferred to the Investment and Interest Reserve, Ordinary Disability Benefit Reserve, Expense Reserve, Prior Service Annuity Reserve, or City Contribution Reserve in the order named, to remove any deficiency then existing in such reserves.
40 ILCS 5/6-197