35 ILCS 630/6
Except as provided hereinafter in this Section, on or before the last day of each month, each retailer maintaining a place of business in this State shall make a return to the Department for the preceding calendar month, stating:
Any taxpayer required to make payments under this Section may make the payments by electronic funds transfer. The Department shall adopt rules necessary to effectuate a program of electronic funds transfer. Any taxpayer who has average monthly tax billings due to the Department under this Act and the Simplified Municipal Telecommunications Tax Act that exceed $1,000 shall make all payments by electronic funds transfer as required by rules of the Department and shall file the return required by this Section by electronic means as required by rules of the Department.
If the retailer's average monthly tax billings due to the Department under this Act and the Simplified Municipal Telecommunications Tax Act do not exceed $1,000, the Department may authorize his returns to be filed on a quarter annual basis, with the return for January, February and March of a given year being due by April 30 of such year; with the return for April, May and June of a given year being due by July 31st of such year; with the return for July, August and September of a given year being due by October 31st of such year; and with the return of October, November and December of a given year being due by January 31st of the following year.
If the retailer is otherwise required to file a monthly or quarterly return and if the retailer's average monthly tax billings due to the Department under this Act and the Simplified Municipal Telecommunications Tax Act do not exceed $400, the Department may authorize his or her return to be filed on an annual basis, with the return for a given year being due by January 31st of the following year.
Notwithstanding any other provision of this Article containing the time within which a retailer may file his return, in the case of any retailer who ceases to engage in a kind of business which makes him responsible for filing returns under this Article, such retailer shall file a final return under this Article with the Department not more than one month after discontinuing such business.
In making such return, the retailer shall determine the value of any consideration other than money received by him and he shall include such value in his return. Such determination shall be subject to review and revision by the Department in the manner hereinafter provided for the correction of returns.
Each retailer whose average monthly liability to the Department under this Article and the Simplified Municipal Telecommunications Tax Act was $25,000 or more during the preceding calendar year, excluding the month of highest liability and the month of lowest liability in such calendar year, and who is not operated by a unit of local government, shall make estimated payments to the Department on or before the 7th, 15th, 22nd and last day of the month during which tax collection liability to the Department is incurred in an amount not less than the lower of either 22.5% of the retailer's actual tax collections for the month or 25% of the retailer's actual tax collections for the same calendar month of the preceding year. The amount of such quarter monthly payments shall be credited against the final liability of the retailer's return for that month. Any outstanding credit, approved by the Department, arising from the retailer's overpayment of its final liability for any month may be applied to reduce the amount of any subsequent quarter monthly payment or credited against the final liability of the retailer's return for any subsequent month. If any quarter monthly payment is not paid at the time or in the amount required by this Section, the retailer shall be liable for penalty and interest on the difference between the minimum amount due as a payment and the amount of such payment actually and timely paid, except insofar as the retailer has previously made payments for that month to the Department in excess of the minimum payments previously due.
The retailer making the return herein provided for shall, at the time of making such return, pay to the Department the amount of tax herein imposed, less a discount of 1% which is allowed to reimburse the retailer for the expenses incurred in keeping records, billing the customer, preparing and filing returns, remitting the tax, and supplying data to the Department upon request. No discount may be claimed by a retailer on returns not timely filed and for taxes not timely remitted.
If any payment provided for in this Section exceeds the retailer's liabilities under this Act, as shown on an original return, the Department may authorize the retailer to credit such excess payment against liability subsequently to be remitted to the Department under this Act, in accordance with reasonable rules adopted by the Department. If the Department subsequently determines that all or any part of the credit taken was not actually due to the retailer, the retailer's discount shall be reduced by an amount equal to the difference between the discount as applied to the credit taken and that actually due, and that retailer shall be liable for penalties and interest on such difference.
On and after the effective date of this Article of 1985, of the moneys received by the Department of Revenue pursuant to this Article, other than moneys received pursuant to the additional taxes imposed by Public Act 90-548:
On and after February 1, 1998, however, of the moneys received by the Department of Revenue pursuant to the additional taxes imposed by Public Act 90-548, one-half shall be deposited into the School Infrastructure Fund and one-half shall be deposited into the Common School Fund. On and after the effective date of this amendatory Act of the 91st General Assembly, if in any fiscal year the total of the moneys deposited into the School Infrastructure Fund under this Act is less than the total of the moneys deposited into that Fund from the additional taxes imposed by Public Act 90-548 during fiscal year 1999, then, as soon as possible after the close of the fiscal year, the Comptroller shall order transferred and the Treasurer shall transfer from the General Revenue Fund to the School Infrastructure Fund an amount equal to the difference between the fiscal year total deposits and the total amount deposited into the Fund in fiscal year 1999.
35 ILCS 630/6