820 ILCS 405/2201.1
The Director shall quarterly furnish each employer with a statement of credit balances in the employer's account where the balances with respect to all contributions, interest and penalties combined equal or exceed $2. Under regulations prescribed by the Director and subject to the limitations of Section 2201, the employer may file a request for an adjustment or refund of the amount erroneously paid. Interest shall be paid on refunds of erroneously paid contributions, penalties and interest imposed by this Act, except that if any refund is mailed by the Director within 90 days after the date of the refund claim, no interest shall be due or paid. The interest shall begin to accrue as of the date of the refund claim and shall be paid at the rate of 1.5% per month computed at the rate of 12/365 of 1.5% for each day or fraction thereof. Interest paid pursuant to this Section shall be paid from monies in the special administrative account established by Sections 2100 and 2101. This Section shall apply only to refunds of contributions, penalties and interest which were paid as the result of wages paid after January 1, 1988.
820 ILCS 405/2201.1