Starting in the early 1990s, countries in southern Europe experienced low productivity growth alongside declining real interest rates. We use data for manufacturing ﬁrms in Spain between 1999 and 2012 to document a signiﬁcant increase in the dispersion of the return to capital across ﬁrms, a stable dispersion of the return to labor, and a signiﬁcant increase in productivity losses from capital misallocation over time. We develop a model with size-dependent ﬁnancial frictions that is consistent with important aspects of ﬁrms’ behavior in production and balance sheet data. We illustrate how the decline in the real interest rate, often attributed to the euro convergence process, leads to a signiﬁcant decline in sectoral total factor productivity as capital inﬂows are misallocated toward ﬁrms that have higher net worth but are not necessarily more productive. We show that similar trends in dispersion and productivity losses are observed in Italy and Portugal but not in Germany, France, and Norway.