40% of Japanese investors think there is a risk of a US default

I've been wondering exactly how much money the US can borrow for stimulus before we start running into sovereign debt problems.  Well, here's one piece of data:

Forty percent of Japanese investors said there is a risk that the U.S. government will default on its debt, a survey published by Barclays Capital showed.

Almost 34 percent of the 66 respondents in the poll sent to Japanese institutional investors from Jan. 26 to Jan. 28 said there is a "significant" or "slight" risk that the U.S. will lose its AAA sovereign debt rating this year. Twenty-two percent said they were concerned about the credit risk of German government bonds. China surpassed Japan in September to become the biggest foreign holder of U.S. Treasuries.

I don't know how much of this is related to the $815 squintillion stimulus, or whatever it is we're proposing to spend this week.  There are other reasons to worry about US debt, like the downturn, the dollar, and our entitlement problems.  But when the citizens of a country with a debt-to-GDP ratio of 1 and more than a decade of economic stagnation behind them start complaining that you're not such a good credit risk, it's time to start worrying.