Ill. Admin. Code tit. 86, § 131.120
a) "Gross Receipts" and "Separate Transactions" Defined. The following definitions must be applied by a remote retailer when determining if it meets either of the thresholds establishing tax remittance obligations:
3) "Entering into a Sale" occurs when a remote retailer has taken action that binds it to a sale. This may occur even though the tangible personal property that has been sold has not yet shipped to the purchaser.
EXAMPLE: On December 15, 2020, a remote retailer takes actions binding it to a sale that is scheduled for shipment on January 15, 2021. This sale must be included in the calculation used to determine the remote retailer's sales transactions for its initial lookback period under Section 131.115(b) (i.e., the lookback period of January 1, 2020 through December 31, 2020).
4) "Separate Transactions" means sales transactions which are documented on separate invoices, regardless of the manner in which the tangible personal property is delivered to the purchaser.
EXAMPLE 1: A purchaser orders 12 items of clothing from a remote retailer. He receives an invoice confirming his order of 12 items. However, due to a back order, 3 of the clothing items are shipped separately from the other 9 items. Shipment of the 3 back-ordered items, even with a separate shipping invoice, is not considered a separate transaction because the original transaction was invoiced as one sale.
EXAMPLE 2: A purchaser places an order of home repair tools at 8:00 a.m. from a remote retailer. She receives an invoice confirming her order at 8:15 a.m. At 2:00 p.m., the purchaser realizes she needs 5 other tools to complete the job, and orders these tools from the same remote retailer. The remote retailer confirms this order with a separate invoice. In this example, two different transactions have occurred. This is the case, even if the remote retailer sends all the ordered tools to the purchaser in one package.
EXAMPLE 3: A parent places an order with a remote retailer for care packages to be delivered to his or her son's dormitory at 8 scheduled intervals during the school year. Each delivery is separately invoiced. These are counted as 8 separate transactions.
b) Transactions that are included or excluded in determining if either of the thresholds establishing tax remittance obligations are met. A remote retailer must apply the following provisions in determining whether a transaction should be included or excluded for purposes of determining if it meets either of the thresholds establishing tax remittance obligations:
1) Sales for resale must be excluded. (See 86 Ill. Adm. Code 130.210.)
EXAMPLE: A remote retailer makes a sale of seedlings to Company B. Company B provides a resale certificate indicating that 60% of the seedlings will be sold to customers at retail (a purchase for resale) and that it will use 40% of the seedlings in its landscaping business (a purchase for use). When calculating its threshold using gross receipts, it should include only 40% of the gross receipts from this sale. When calculating its threshold using transactions, however, the remote retailer must include the entire transaction with Company B.
(Source: Amended at 46 Ill. Reg. 2697, effective January 26, 2022)