Sometimes you may spend too much money and end a trade offers phase in the red. The Deal Book informs you of this fact and lists your borrowing limit. If you go over this limit you will receive a warning about a forced sale of your warehouse stockpile. The prices paid during a forced sale are quite low and it is a good idea to avoid it if you can. Additionally, you cannot purchase anything during your turn, nor can you give orders that require an expenditure, as long as you are too far in debt.
On the other hand, there is nothing wrong with borrowing as long as you stay within your credit limit. In fact, since the world banking community likes to have your country in debt, every time you borrow and then repay the money your credit limit for the future increases. Credit limit also depends on the industrial strength of your Great Power.
