Cross-border funding between banks collapsed following the bankruptcy of Lehman Brothers, but the withdrawal of funding was not uniform across countries. This column argues that the composition of cross-border bank-to-bank funding can help to explain why. Interbank funding between unrelated banks is particularly vulnerable to global shocks, but intragroup funding between related banks can act as a stabilising force, particularly for advanced economies with a high share of global parent banks. Policymakers should look at disaggregated cross-border bank-to-bank flows, as doing otherwise could result in a misleading assessment of financial stability risks.