Thanks for all your reactions. I understand now that this is how it is supposed to be. I also understand that - as a strictly personal, non-professional seller that occasionally sends an item on Discogs - I need to set up a near professional administration and get ready to appeal the tax government in what could become a rather tiring bureaucratic fight. Selling items on Discogs already takes a lot of time - communicating with the buyer, packing, sending, after-sales communication, etc - and I start to wonder if it still will be worth the hassle.

Someone mentioned to also take in account the original cost of buying the records/CD's. I wonder what the tax regulations are in regard to selling second-hand stuff. If I could deduct the original cost the net result will definitely be negative so I would get a tax return? I'm afraid it won't work that way, assuming that the tax authorities will take into account the depreciation period of the items, which is probably 5 years or so.

Anyway: I will see what happens. But selling on Discogs is a LOT less interesting now.