Investors borrow money when they need it, but they also borrow to make a profit. If you can borrow money at 5% interest and invest it to earn 6%, you make a profit of 1%. That's called leveraging and it is profitable. Do you remember a guy named Aristotle Onassis? That's how he got rich. That's why an investor like Donald Trump is not in a rush to pay off all his debts. As long as he can leverage the money, he maintains the loans and makes a profit.