86 Ill. Adm. Code 950.450
Limitations
Section 950.450 Limitations
a)
No notice of proposed assessment may be
issued with respect to a calendar year after June 30 of the fourth subsequent
calendar year.
(
Section 85(f) of the Act)
b)
No claim for refund may be filed more than 1
year after the date of payment of the amount to be refunded.
(
Section
85(f) of the Act)