215 ILCS 5/531.13
In the event the aggregate Class A, B and C assessments for all member insurers do not exceed $3,000,000 in any one calendar year, no member insurer shall receive a tax offset. However, for any one calendar year before 1998 in which the total of such assessments exceeds $3,000,000, the amount in excess of $3,000,000 shall be subject to a tax offset to the extent of 20% of the amount of such assessment for each of the 5 calendar years following the year in which such assessment was paid, and ending prior to January 1, 2003, and each member insurer may offset the proportionate amount of such excess paid by the member insurer against its liabilities for the tax imposed by subsections (a) and (b) of Section 201 of the Illinois Income Tax Act. The provisions of this Section shall expire and be given no effect for any tax period commencing on and after January 1, 2003.
215 ILCS 5/531.13