Section 40 ILCS 5/6-171 - Contributions by city for certain annuities(a) Each city shall contribute annually, from the sum produced by tax levy herein authorized, all sums required for the purposes of this Article, other than those stated in this Section.(b) Thereafter, the balance of the sum produced by the tax levy shall be applied to provide prior service and widow's prior service annuities under this Article, and all annuities, pensions and benefits which have been or shall be granted under "An Act to provide for a firemen's pension fund and to create a board of trustees to administer said pension fund in cities having a population exceeding two hundred thousand (200,000) inhabitants", filed June 14, 1917, as amended, and also for the purpose of providing that part of any annuity described in Sections 6-123, 6-128, 6-141 and 6-164 of this Article for which moneys are not provided under this Article, and to make possible the transfer of reserves from the investment and interest reserve to other reserves.(c) All amounts contributed by the city for the purposes of this Section shall be credited to the prior service annuity reserve except that contributions made for the purposes of Section 6-164 shall be credited to the automatic increase reserve. When the balance of each of these reserves equals the liabilities of each such reserve (including, in addition to all other liabilities of such reserve, the present value, according to the applicable mortality table, and applicable interest rate, of all annuities, present or prospective, or parts of such annuities chargeable to that reserve) the city shall cease to contribute the sum stated in paragraph (b) of this Section; provided, if at any time the balance of the investment and interest reserve is not sufficient to permit a transfer of moneys from that reserve to any other reserve, in accordance with the provisions of this Article, the city shall, as soon as practicable thereafter, contribute sums sufficient to make possible such transfer of the amounts required.(d) If by reason of annexation of territory and the employment by the city of any fireman employed in the territory at the time of the annexation, after the city has ceased to contribute as provided in paragraph (b) of this Section, contributions to provide prior service and widow's prior service annuity for such fireman becomes necessary for such annuity purposes, the city shall, as soon as practicable thereafter, contribute sums sufficient to provide such annuities.