86 Ill. Adm. Code 150.115
How To Determine Effective Rate
Section 150
Section 150.115 How To
Determine Effective Rate
a) For the purposes of the Use Tax Act, any tax liability
incurred with respect to a sale of tangible personal property made in the
regular course of business shall be computed by applying, to the selling price
of such sale, the tax rate in effect as of the date of delivery of such
property: Provided that if delivery occurs after the tax rate changes, in a
transaction in which payments on the selling price were made by the purchaser
before the date of the rate change and tax was paid by the purchaser to the seller
or to the Department on such payments when they were made by the purchaser in
accordance with 86 Ill. Adm. Code 130.430 at the rate which was in effect when
such payments were made to the seller, no additional tax will be due or credit
allowed because of delivery of the property occurring after the rate change.
b) Furthermore, in the case of sales of building materials to
real estate improvement construction contractors for use in performing
construction contracts for third persons, if such property is delivered to the
contractor after the effective date of a rate increase but will be used in
performing a binding construction contract which was entered into before the
effective date of the increase and under which the contractor is legally unable
to shift the burden of the tax rate increase to his customer, the applicable
tax rate will be the rate which was in effect before the effective date of the
rate increase. Before a supplier may deliver materials to a construction
contractor after the effective date of a tax rate increase at the rate which
was in effect prior thereto, the purchasing contractor must give such supplier
a written, signed certification stating that specifically described materials
are being purchased for use in performing a binding contract which was entered
into before the effective date of the rate increase (specifying such date) and
under which the contractor is legally unable to shift the burden of the tax
rate increase to his customer, identifying the construction contract in question
by its date and by naming the contractor's customer under the contract and by
describing the nature of the construction work involved, and by giving the
location of the job site where the construction contract is being performed or
is to be performed.