Borders Order Starts with UPS then Transferred to USPS

This is kind of interesting. I ordered something online the other day. UPS processed the package first and then handed it off to the US Postal Service (USPS). I knew that UPS actually handled orders for a number of firms in the sense that they actually handle inventory in addition to shipping. But, this is the first time I’ve seen a packaged handed off from UPS to USPS for the final delivery.