On Wall Street, calling some strategy a “black box” is an epithet. The term implies financial flimflammery may be at play. Opacity may conceal trickery. Bernie Madoff had a black-box model that supposedly helped him pick winning stocks. The deception was in the details, or, rather, the lack of them.
Credit rating agencies such as S&P really place a lot of emphasis on two financial metrics: the ratio of net debt to GDP and the ratio of net interest payments to government revenues. When you look at those two factors, Goldman Sachs concludes “that the US is already at the outer edge of AAA territory. ” (Thank goodness for the supremacy of the dollar.) Look at the pretty chart from GS: