In his November 10 Op-Ed in this paper, David Tripe, an academic in banking studies, assays the significance of the downgrade of New Zealand debt from Aaa to AA.
While informative, the article appears flawed by political bias. It's also lacking in context.
When we talk about credit ratings of debt we're implicitly addressing investors who would be willing to assume that debt for a reasonable return based upon the degree of risk involved. The ratings given by the agencies, S&P; or Moody's have been presumed to provide guidance as to the degree of risk.
The trouble is that the credibility of the agencies, themselves, has been shaken. After the near collapse of the US financial system caused in large part by the accumulation of mortgage backed debt by many financial institutions, it was found that the agencies had rated that debt as AAA, despite the fact that internal emails of some of the issuing brokerages described that debt in terms such as "mountains of excrement". When the rating agency heads were called before Congress to explain their ratings they universally claimed "it was only an opinion".
The subsequent lack of attention that investors gave to those "opinions" can be seen by the effect which the downgrade of US debt had on the market: absolutely nothing.