Case A) Let's say I buy BTC mit EUR today (February 2016), and immediately buy an altcoin with them. I keep them in a safe (coldwallet) and eventually cash them back to BTC in, let's say November 2016. Ideally I'll have quite some more BTCs than at the beginning. When can I cash them back to EUR free of tax? Still February 2017 or November 2017?
I would handle it like this (I try it to explain by an example):
You bought 1 BTC for 100 . Bought an Altcoin for 1 BTC on Feb 2016, sell the Altcoin on November 2016 for 1,1 BTC.
You didn´t hold them longer than one year.
If the price is still the same..
earning - buyprice = profit
1,1 BTC * 100 - 1 BTC * 100 = 10 Euro profit
It gets funny if the BTC price rises to 150 Euro / BTC, but here im not sure
Case A)
1,1 BTC * 150 - 1 BTC* 100 = 65 profit -> new buyprice for 1,1 BTC 165 Euro
or
Case B)
0,1 BTC * 150 = 15 profit -> New Buyprice = 1,0 BTC for 100 + 0,15 for 0 = new buyprice for 1,1 BTC 100 Euro
You got the BTC on Nov 2016 so you must wait until Nov 2017 to sell them.
Case B) Similar to B, but instead of keeping the altcoin safe in a coldwallet, I'm trading with them for months long. Eventually converting to/from BTC/altcoin(s) back and forth. In November 2016 I decide I've won/lost enough and want to trade back to EUR. Which date would make this taxfree? February or November 2017?
After each trade with full amount of btc the "free-Tax"-Timer resets.
You must provide them everything, if you hold the coins for over one year. Then its enought to show them your BTC-Wallet with the date of deposit. If you trade them you can try to send them the summary of your trading in one sheet with your profit / loss. But maybe they wanna see each trade @ an excel-sheet.
This is my opinion, handle with care
