You have two bank accounts, the Standard and the Game.
The Standard account gains 7% interest a night, the Game 14%.
(There aren't any games for the Game account balance to bet on.)
During maintanence, any money in an account over 50,000,000 is taken as tax.
As well as Sacre Base, you can access your bank accounts in several towns across the wasteland.
High-ranking player taxEdit
Adventurers from level 10 to 19 pay 10% above appraise for items bought from stores; adventurers level 20 and over pay 25% more.
Since you'll spend most of your career above level 25, store prices on this wiki include the 25% high-ranking player tax.
The money taken from large bank balances and charged to high-level players by stores is redistributed amongst the adventurers.
It appears in your Standard account.