"Between 40 and 45 per cent of the world's wealth has been destroyed in little less than a year and a half...This is absolutely unprecedented in our lifetime," Mr Schwarzman is quoted as having said.

But the US government is committed to the preservation of financial institutions, he said, and will do whatever it takes to restart the economy.

US Treasury Secretary Timothy Geithner plans to unfreeze credit markets through a new programme that will combine public and private capital in a fund that would buy bank toxic assets of up to $1 trillion.

"In all likelihood, that will have the private sector buy troubled assets to clean the banks out in terms of providing leverage... so that we can get more money back into the banking system," Mr Schwarzman said.

He expects the private sector to end up making "some good money doing that," but added there were complex issues on how to price toxic assets.

He put part of the blame for the financial crisis on credit rating agencies.

"What's pretty clear is that, if you were looking for one culprit out of the many, many, many culprits, you have to point your finger at the rating agencies," he said.