If they were commingling every single report would be a lie.
Also, they explicitly state that:
>Generally, we recognize gross revenue from items we sell from our inventory as product sales and recognize our net share of revenue of items sold by third-party sellers as service sales.
If they were commingling, those figures would be a lie.
The reason that would be lie is that Amazon has defended itself from product liability lawsuits for harms caused by defective products sold by third parties by repeatedly claiming in court that they do not take title to the goods in their possession that are supplied by third parties.
When you take title to something it is yours.
If it is yours, you need to include its value in an inventory valuation.
If inventory that you have title to and inventory you do not have title to is commingled there is no way to track which of the two have been sold, who holds title to what remains in inventory, and what that is worth.
Their inventory valuation would be a lie, their product sales figures would be a lie, and their service sales figures would be a lie. The amount of insurance they carry would be wrong, and that would open them up to legal vulnerabilities if anyone can demonstrate that the toaster they bought from a third-party seller which exploded was actually a toaster Amazon had title to and was shipped to them due to being commingled.
The only thing an investor has to do to sue the shit out of amazon is establish that their numbers are wrong, and are wrong on purpose, and they have been harmed by their numbers being wrong.
