Can you explain how that is possible? In my understanding, if the interest rate is negative then the bank is, in other words, charging you a fee to keep your money there plus you are still taking a hit from inflation so at least if you take all your money out of the bank you are only taking the hit from inflation and not having to pay the bank a monthly fee to do so.
Even then leaving your money in the bank at a negative interest rate would not be better than having it in a mattress discounting physical theft risks of course.
