A pending period is usually related to mobile shopping offers.
A pending period is a length of time, in days, that your completed offer is placed on hold until Ibotta can verify your purchase. A pending period usually coincides with a return or exchange period, and varies depending on the retailer.
The pending period for a specific offer can be found in the offer details. The pending period is "up to X days", therefore some purchases may post earlier than the pending period's completion. Also, a pending period will start on the day that your purchase posts to your account as pending rather than the day that the purchase was made.
Note: Most mobile shopping bonuses are credited when the pending period is completed. Please be sure to check this information out when you make your purchase.