Because the number of the money in your bank account is stored in 32 bit, the maximum value can be slightly over 2 billion. To fix this, the board will invest multiple hundred million into an "investment fund" which you have no insight to at all.
This is just not contemporary. If you make good transfers with a big club, you can reach that point in 5 years, easily. It simply destroys my motivation to search for profit-making transfers completely, because it won't matter anymore anyways. Just turn that number into 64 bit. Can't be that hard.