catcrab is right, its better to scale down the total amount of creds down to a sensible level where rk missions or classic cred farming methods can not only maintain your cred supply but add to it.
a basic level 100 rk mish will net you something like 100k if you sell everything and kill every mob, if the person had a fortune of 1m that would be a lot of money to them. For someone with 10bil, what is 100k really?