Bearing in mind that more than 40 percent of US corporate profits come from a financial sector whose profits have been bloated by leveraged carry trading,the scope for trouble is considerable.We have a system overloaded with debt in the household and public sectors and stretched by financial imbalances.Yet many in the markets are saying,as with technology in 1999,that this time it is different.Encouraged by the relentless optimism of the great helmsman at the Federal Reserve they are convinced we shall all muddle through.