The importance of sovereign credit ratings and Eurobonds issued by governments have come to the fore in Africa in the last decade. We examine whether changes in sovereign credit ratings impact Eurobond yields in 8 countries over the period of 2014–2019. Our approach reviews rating changes impact on Eurobond yields utilising the event study methodology. Our findings reflect that, on average, close to a third of rating actions directly impact bond yields in African countries. The statistically significant events include the downgrades of South Africa and Namibia to non-investment grade in 2017 reflecting critical transitions and bond investors’ reactions. Overall, the low percentage of a third, relative to previous international studies, suggests that largely rating changes are anticipated, do not have much new information and perhaps the perceived power of credit rating agencies may be overstated. In our view, the results reflect that pre-announcements of rating review dates since 2014 makes rating actions predictable and less impactful to bond yields. In addition, they reflect that bond investors adjust in real time as new information come in, resulting in less reliance on the opinions of CRAs and using their own assessments.

在过去十年中，各国政府发行的主权信用评级和欧洲债券的重要性在非洲脱颖而出。我们研究了主权信用评级的变化是否会影响 8 个国家在 2014-2019 年期间的欧洲债券收益率。我们的方法利用事件研究方法审查评级变化对欧洲债券收益率的影响。我们的调查结果反映，平均而言，近三分之一的评级行动直接影响非洲国家的债券收益率。具有统计意义的事件包括南非和纳米比亚在 2017 年被下调至非投资级，反映了关键转变和债券投资者的反应。总体而言，与之前的国际研究相比，三分之一的比例较低，这表明预计会有很大的评级变化，没有太多新信息，或许信用评级机构的感知力量可能被夸大了。我们认为，结果反映了自 2014 年以来的评级审查日期的预先公布，使评级行动可预测，对债券收益率的影响较小。此外，他们反映债券投资者会随着新信息的进入实时调整，从而减少依赖信用评级机构的意见和使用自己的评估。