In a settlement, you can find the Trading Post, which gives you access to the Auction. The shop has a banner with a raven on a green background.
Auction is global for the server. Difference only in current town trade tax.
The Company that claims the territory of the settlement sets the tax on the sold / bought items of the Auction. The player also pays a certain amount of gold for placing his order to buy / sell, which also depends on the time, for how many days the lot is placed.
When placing an order for sale, you see items that are in your inventory and items in your warehouse in this city.
Not sold items are placed in the warehouse of the city.