The lower the credit rating of the borrower, the higher the cost of borrowing and the higher the yield of the creditor  On August 5th, 2011, S & P downgraded the sovereign credit rating of the United States from AAA to AA+  As a matter of common sense, investors should reduce their holdings of US Treasuries when they are in safe-haven demand, thus pushing prices lower and yields higher  However, on Aug  8, the price of US Treasuries rose and the yield fell, and the yield on the latest 10-year Treasury note fell to 2
34%, the lowest so far this year
Compared with the bonds of the European Union, Japan and other countries, US Treasuries are still relatively safe and liquid investments.