一、全球外汇市场回顾2011年8月5日,全球三大评级公司之一标准普尔发布报告,称由于美国政治风险和债务负担不断上升,将美国主权信用评级从AAA下调至AA+,前景展望为负面。此举引发全球金融市场发生巨大动荡。但大多数机构认为,以美国经济和美国国债 I. Review of the Global Foreign Exchange Market On August 5, 2011, Standard & Poor’s, one of the world’s top three rating agencies, released a report saying the U.S. sovereign credit rating was downgraded from AAA to AA + due to rising political risk and debt burden in the United States, with a prospective outlook of Negative. This triggered a huge turmoil in global financial markets. But most agencies think of the U.S. economy and U.S. Treasuries