Ill. Admin. Code tit. 86, § 125.110
a) Rental Purchase Agreement Occupation Tax
4) The RPOT is solely the responsibility of the merchant.
b) Rental Purchase Agreement Use Tax
c) How To Determine Effective Rate
RPOT liability is computed by applying to the gross receipts the tax rate in effect at the time a consumer takes possession of rented merchandise. Where a rate change takes effect during a consumer's possession, all rental receipts received from that consumer after the effective date of the rate change are subject to the new rate. If a consumer takes possession after a rate change in a rental transaction in which the merchant received rental receipts before the date of the rate change and the tax was paid on such receipts when received by the merchant at the rate in effect when the merchant received those receipts, no additional tax will be due or credit allowed because the consumer took possession after the effective date of the rate change.