"Retroactive" Tax on Deposits

Remember this post?

Spain will now retroactively tax bank deposits to January 1, 2014 stating the move will boost growth and job creation. And for your information, it's 6 July 2014 today. Luckily it's only 0.03% tax. But it's a lot of money for those wealthy millionaires.

 

I have never heard of such things. How can you retroactively tax deposits? Let's say i used up all my money in February 2014 and it was a lot of money. Then I would be bankrupt now due to the "retroactive tax".

Also, let's say I put all my cash in gold in February 2014, then I still have to be taxed on the deposits from before February 2014. 

Your money isn't safe, it's better to act now, before it's too late. If you act too late, you'll be retroactively taxed before you know it.