On the market you buy a fungible asset, so the auction can be batched up between multiple buyers and sellers.  On eBay you can&#x27;t batch the things sellers are selling because a key part of what buyers are supposed to be doing is things like checking an individual seller&#x27;s feedback and weighing whether he low price is worth risking it, or carefully reading the description to make sure you aren&#x27;t buying a cardboard cutout picture of the product, a product box, or a car that was sawed in half and photographed so that it could be sold to two people instead of one.  Plus a lot of the products are used and have one-off descriptions of flaws.<p>EBay doesn&#x27;t have the same kind of clearing houses and broker-dealer regulations that would make sold items be anything like stock shares, even if they were all brand new and retail packaged.