Regulation needs effective supervision; but regulated entities may deviate with unobserved actions. For identification, we analyze banks, exploiting ECB’s asset-quality-review (AQR) and supervisory security and credit registers. After AQR announcement, reviewed banks reduce riskier securities...

We show that banks' risk exposure in one asset category affects how they report regulatory risk weights for another asset category. Specifically, banks report lower credit risk weights for their loan portfolio when they face higher risk exposure in their trading book. This relationship is...