86 Ill. Adm. Code 150.120
Effective Date of New Taxes
Section 150
Section 150.120 Effective
Date of New Taxes
When something that has been
exempted becomes liable as to purchases that are made on and after some
particular date, the date of purchase for this purpose shall be deemed to be
the date of the delivery of the property. This is true even if such delivery is
made under a contract that was entered into before the effective date of the
new tax.