LAUSR

How does government partisanship influence sovereign credit ratings of developed countries? Given the convergence of fiscal and monetary outcomes between left and right governments in the past decades, credit rating agencies (CRAs) should in principle not discriminate according to ideology. However, we hypothesize that CRAs might lower ratings for left governments as a strategy to limit negative policy and market surprises as they strive to keep ratings stable over the medium term. A panel analysis of Standard & Poor’s, Moody’s, and Fitch’s rating actions for 23 Organisation for Economic Co-Operation and Development (OECD) countries from 1995 to 2014 shows that left executives and the electoral victory of nonincumbent left executives are associated with significantly higher probabilities of negative rating changes. We find no evidence of similar systematic partisan bias in spreads on government bonds, but spreads do adjust to partisan-biased downgrades. This suggests that CRAs may introduce partisan discrimination into sovereign credit markets.