The European Central Bank published Working Paper No 3031 examining how disclosure of supervisory Pillar 2 capital requirements affects market efficiency, comparing banks that publicly disclose their Pillar 2 Requirements (P2R) with those that remain opaque. The paper concludes that greater supervisory transparency is associated with lower funding costs and improves the market’s ability to differentiate between safer and riskier banks. Using bank-level supervisory and balance sheet data and exploiting variation in P2R disclosure practices among Banking Union Significant Institutions over 2017-2020, the authors estimate an average 11.5% reduction in funding costs for disclosing banks versus non-disclosing peers. The effect is heterogeneous, with the safest quartile of disclosing banks, defined as those with a Common Equity Tier 1 P2R below 1.5% of risk-weighted assets, benefiting most with average funding costs around 31.1% lower. The analysis also documents a mispricing pattern under opacity, where higher-risk non-disclosing banks can face lower funding costs, and finds that disclosure counteracts this by aligning funding costs more closely with supervisory risk assessments.