Every eBay seller has to give their name, address, cc details at time of registration. Every eBay transaction (sale) is available for scrutiny by the tax authorities (English/French/US etc.) During a rather expensive run-in with a not very friendly UK tax inspector I was told the following :- "Sir, you sell an item on eBay - aquired 20 years ago, bought last week, inherited or found at the roadside - if I (tax inspector) think you placed that item on eBay to make a profit.......then I shall treat that profit as taxable income" Forget about capital gains etc. they class it as TRADING!