70 ILCS 1825/10
All bonds, whether general obligation or revenue, shall be sold by the Board in such manner as the Board shall determine, except that if issued to bear interest at the maximum rate permitted in "An Act to authorize public corporations to issue bonds, other evidences of indebtedness and tax anticipation warrants subject to interest rate limitations set forth therein", approved May 26, 1970, as now or hereafter amended, the bonds shall be sold for not less than par and accrued interest and except that the selling price of bonds bearing interest at a rate less than the maximum rate permitted in that Act shall be such that the interest cost to the District of the money received from the bond sale shall not exceed such maximum rate annually computed to absolute maturity of the bonds according to standard tables of bond values.
70 ILCS 1825/10