Switzerland is a new entry this quarter after engaging in quantitative easing; Portugal has dropped out in the wake of a downgrade by S&P and is now ranked 14th.
Before you ask, the U.K. is ranked 18th, behind China (17th).
Implied Ratings are calculated using a proprietary model developed by CMA and fed with CDS pricing data
from CMA DataVision.
Source: CMA DataVision Global Sovereign Credit Risk Report Q2-2009
Related:
The World’s Safest Sovereign Debt