ECB paper: fixed-rate banking systems transmit rate rises more strongly — if solvency bites

Serguey Asael Shinder17 October 2026, 09:072 min read

ECB Working Paper No 3299 (October 2026), by Jorge Abad, Saki Bigio, Salomon Garcia-Villegas, Joël Marbet and Galo Nuño, asks how differences in banks' interest-rate-risk exposure shape the way monetary policy passes through to lending. It is research within the ESCB's ChaMP network and carries the usual disclaimer that it does not represent the ECB's views. (This is a model-based study, and the results below are the paper's own; the analysis desk treats it as such.)

The central result. The authors build a quantitative macroeconomic model of heterogeneous banks and establish what they call an irrelevance result: whether a banking system is predominantly fixed-rate or variable-rate matters for transmission only when bank solvency concerns become relevant. Away from the solvency threshold, the difference washes out. But calibrated to the euro area, idiosyncratic default risk pushes a substantial share of banks toward that threshold, which is what makes the heterogeneity quantitatively important in practice.

The mechanism when it bites. When policy rates rise, fixed-rate banks suffer net-interest-margin compression — their funding costs go up while income from legacy loans does not — which erodes capital and triggers sharper deleveraging. The paper puts a number on it: the lending elasticity to monetary policy is one-third larger in fixed-rate economies. The effect extends to financial stability: tightening raises bank-failure rates in fixed-rate systems while lowering them in variable-rate systems, because in the latter rising rates lift income on existing loans.

Why it matters for policy. The authors read these results as a rationale for coordinating macroprudential and monetary policy, and for monetary-policy gradualism — because the same tightening does more damage to lending and to bank solvency where fixed-rate lending dominates, moving slowly limits that damage. The JEL codes (E51, E52, G21, G28) place it in monetary policy and banking regulation.

As a 99-page working paper, this is a quantitative modelling exercise, not an ECB policy statement or a claim about the current stance; its force is conditional on the model and its euro-area calibration. The practical takeaway for readers of rate decisions is the conditional one the paper itself draws: the composition of a banking system (how much lending is fixed- versus variable-rate) can change how strongly a rate move transmits, but mainly through the solvency channel.

Source: European Central Bank, Working Paper Series No 3299, "The heterogeneous bank lending channel of monetary policy" — https://www.ecb.europa.eu//pub/pdf/scpwps/ecb.wp3299~01776adb36.en.pdf