The European Central Bank published its 2025 Macroprudential stress test extension report (MaSTER), a top-down complement to the 2025 EU-wide bottom-up stress test, finding that euro area banks are resilient in the standard adverse scenario but that additional risk channels reveal pockets of vulnerability that support a cautious approach to capital buffers. MaSTER broadens the assessment beyond the EU-wide exercise’s methodological constraints, including the assumption that banks keep lending unchanged. Using a top-down banking sector model, the ECB estimates that under an adverse scenario featuring a prolonged recession, market slump and sticky inflation, banks would reduce lending, slightly improving capital ratios versus a constant-balance-sheet assumption but deepening the downturn via a credit squeeze, with an additional cumulative real GDP contraction of around 2 percentage points after three years. Releasing available macroprudential buffers offsets some pressure on credit supply, although the impact is modest given the currently limited size of releasable buffers. A system-wide model suggests non-bank balance sheet adjustments could amplify price declines, with investment funds facing the largest losses; for banks, the additional average Common Equity Tier 1 (CET1) depletion is limited due to hedging, but banks with weaker hedging can be affected more significantly. For climate risk, adding transition and flood-related physical risk to the scenario increases projected credit risk losses by around 70 basis points in each case, with transition losses largely driven by exposures to energy-intensive sectors; overall net capital depletion rises slightly once all extensions are combined, but remains below the final outcome of the 2023 stress test.