> I'm not sure what you mean. They do track everything, otherwise they couldn't match up your payment for the product with the vendor it actually came from in order to pay them.

They don't, though. All the same-SKU items go into a big box at the warehouse. When you order from a particular seller, they pick one out of that box and send it to you. There's a good chance the specific one they picked out didn't come from that seller's inventory, but another's.

https://www.wsj.com/articles/on-amazon-pooled-merchandise-op...