This paper investigates the determinants of the stocks and flows (both in- and outflows) of nonperforming loans (NPLs) by considering a bank-specific factor that is not adequately analysed in the literature, namely, bank capital buffers. Using unbalanced panel data with 6,087 bank-year observations for the 2006–2018 period and a two-step system generalised method of moments (GMM) estimation, we find that banks with higher levels of capital buffers (both in terms of Tier 1 and total capital) have fewer NPL stocks and generate fewer NPL inflows. When we control for the characteristics of the loan portfolio, real guarantees collected by the bank increase the stocks and flows of new, impaired loans, while personal guarantees favour the outflow of bad loans.

本文通过考虑文献中未充分分析的银行特定因素，即银行资本缓冲，研究了不良贷款 (NPL) 的存量和流量（流入和流出）的决定因素。使用具有 2006-2018 年期间 6,087 个银行年观察值的不平衡面板数据和两步系统广义矩量法 (GMM) 估计，我们发现资本缓冲水平较高的银行（在一级和总资本）拥有较少的不良贷款存量并产生较少的不良贷款流入。当我们控制贷款组合的特征时，银行收取的真实担保增加了新的、减值贷款的存量和流量，而个人担保有利于不良贷款的流出。