A 2026 study by the Bank for International Settlements (BIS) examined the influence of sovereign credit ratings on financial markets since the Greek debt crisis of 2010-2015. The research found that rating downgrades continue to trigger measurable increases in government bond yields, particularly for emerging economies.
However, the impact has diminished compared to the peak of the eurozone crisis. The BIS analysis shows that markets now rely more on alternative indicators such as debt-to-GDP ratios and political stability indexes. The study notes that the 2010 downgrade of Greece to junk status caused a 300-basis-point spike in its 10-year bond yield, while similar downgrades in 2025 produced only a 50-basis-point reaction on average.
Regulatory changes since 2015, including the European Securities and Markets Authority's (ESMA) stricter oversight of rating agencies, have reduced the element of surprise in rating actions. The BIS report concludes that while sovereign ratings remain relevant, their market-moving power has been diluted by increased transparency and the proliferation of independent credit analysis.
