Well the first game actualy had this as a example.
Although this is the 3th game in the series ( ignoring the non global games ) those rules have never changed afaik. The wording isnt at least so this would make them the longest stable rules in the game 😛
When germany captures russia while germany itself is in UK hands germany gets all of russia’s money but cannot spend it. This is the only way to have cash without having a capital.
I think that was about the wording in that manual but it has been a while so it might not be a exact quote.