As a promoter of GOLD token, you should have done your homework better.
@Bttzed03 has posted the relevant things and indeed, it's the daily fee you pay for the storage of the actual gold and it's probably coded in the contract of the token and done automatically. So don't worry, nobody is accessing your key.

I would add that exchanges don't pay this fee so if you want to HOLD and don't want to pay the fee, you can take the risk of keeping the tokens at an exchange.