Beyond fragmentation: unraveling the drivers of yield divergence in the euro area

This paper provides a novel and high-frequency index of sovereign fragmentation in the euro area. The proposed methodology offers a decomposition of sovereign yields into the common trend, market conditions, and fundamentals-based divergence, which are uncorrelated to fragmentation. Therefore, the fragmentation index constitutes a bottom-line indicator for euro area central banks, as it measures disorderly market dynamics in sovereign markets not warranted by fundamentals. In that sense, this paper provides relevant conclusions about the effectiveness of monetary policy interventions, pointing to the significant effect of market stabilisation announcements, such as the Transmission Protection Instrument (TPI), in reducing sovereign fragmentation. I contribute to the literature by estimating the uncorrelated drivers of euro area yields divergence using a restricted principal components analysis. The estimated factors are then used to assess the effect of fragmentation, market conditions and fundamentals on country yields through several economic regimes, pointing to differences across countries and over time.