I recently received a notification from the Spanish tax agency (AEAT) about a tax audit against me. I wonder if someone has any advice or experience with those things.
Facts:
The period under audit is fiscal years 2015 - 2017 (both inclusive I suppose). It seems they “woke up” now because the statute of limitation (“prescripción” in Spanish) for year 2015 is about to expire (tax return for 2015 had to be filed by June 30th 2016, the statute of limitation expires four years after that).
I have been selling say 10 000 euros worth of btc per month, except for last 2 months, when I was close to 100 000 euros. Some of them were made throught bisq, but only minority.
I included my profits in my tax returns and paid tax on them, but they probably do not like how little information I gave. I just summed all the euros from sales, subtracted the amount spent on buying btc, and filed as capital income.
Rant:
One could say that this is pretty expected, and the threat is pretty low if I paid as I say. But this assumes that they act according to the law, and why would they do that? I already have a disgusting experience with Spanish inquisition (they call themselves Justice for no good reason). I was convicted of petty fraud (180 euros), because I was in the middle of MITM scam, and I should have known that 0.5 % of 1000 euros is 50 euros - the 0.5 % is my profit margin, and it was supposedly too much, so I should have known that the scam is occurring. I still do not know that, I still think 0.5% of 1000 is 5, and pointed it out to no avail. (More details) In another case, I had to pay about 700 euros fine because I was found innocent. Sure, the inquisition will say it was not fine, but fee paid to my lawyer. But by law I am obliged to have a lawyer in any bigger case, and pay him/her even if innocent. And that investigation was totally botched, it was about a phished bank transfer initiated 17/12, but the geniuses asked ISP about connections of day 18/12. (I guess I will write more about that in separate topic, promise it will be my last one. 
) Given this experience, I am rather paranoid.
Edit: “tax audit” is the proper English phrase for Spanish “inspección”