catawikiというオークションサイトのFAQで「margin good」や「margin item」というワードが出てくるのですがどういう意味でしょうか？

以下、文章を抜粋いたします

▼What are new items?
New items are items that are unopened and unused and readily available from retailers or shops.
They contrast with margin goods, which is the term for second-hand objects, collectables, art and antiques.
This difference is relevant to determine the VAT treatment of the sale.

▼How does Catawiki know the item sold is a margin good?
When submitting an item, the seller needs to select if the item qualifies as a margin item by checking the box:
'This is a lot on which I as the seller will not have to pay VAT (e.g. because it’s a so-called margin item)'.