His Web site shows his portfolio posting wild swings between profits to losses, reflecting the risks of borrowing shares that are sold short: If the shares rise too much during the several months that Middleton typically hangs on, he might have to buy them back at higher prices.

FORBES: Magazine Article

It added that policymakers need to put in place measures to "closely monitor and control the risks related to borrowing by local entities, especially local government financing vehicles".

BBC: IMF: Worsening eurozone crisis a 'key risk' to China

And Mr Rubin acknowledged that more should be done, both in rich and poor countries, to reduce the risks of over-borrowing.

ECONOMIST: Global finance

That said, there are substantial costs and risks for Spain in borrowing the money from the eurozone's bailout fund, the EFSF, quite apart from the humiliation of being seen to have its economic policy dictated by Germany.

BBC: Will Spain suffer an Irish bust?

Investors are not yet charging higher risk premiums on government borrowing to take account of these demographic risks.

ECONOMIST: Demography and public finance: Relegation ahead | The

The transactions in question, known as "window dressing, " involve repurchase agreements, or repos, a form of short-term borrowing that allows banks to take bigger trading risks.

WSJ: Ernst & Young Faces Fraud Charges

So gilt prices rise, and the implied borrowing costs for the government fall, when the risks of putting money into companies are perceived to be too great.

BBC: Government becomes banker to the private sector

In contrast, only children, who in theory share many characteristics with first borns, reported the highest instance of taking financial risks at least sometimes, 39 percent, such as borrowing for short-term investments, or investing in risky ventures.

FORBES: One More Reason to Blame Mom and Dad for Your Money Habits?