The International Monetary Fund estimates the world financial system will be more than $US4 trillion worse off when the crisis is over.
In a twice-yearly report on global financial stability, the IMF says banks and other financial institutions will eventually have to write down assets by $US4.1 trillion.
Even if urgent action is taken to clean up the banking system, it says the process will be slow and painful, and delay economic recovery.
The agency says that banks may need $US1.7 trillion dollars in extra capital, which may point towards further bank nationalisations.
In the United States alone, losses are estimated to total $US2.7 trillion.
