Having alt accounts are not allowed (rule number 7 in the in-game rules). Which bank do you invest into? All banks I find have outrageous high debts...😅
Debt means the amount you deposit they owe you, like if i deposit 500$ in my bank it'd be a debt of 500$ meaning the value goes up 500$ but the debt of 500$ means that's a deposit. Also interest rates aren't too important since 1% is the max you can go and the only safe bank with high interest is 0.25% doesn't really do much unless you have a lot of money then you can make 5$ from like 2.5k.