The Bank of England published Staff Working Paper No. 1,156 by Manuel Gloria and Chiara Punzo, presenting a DSGE model in which commercial bank capital requirements become binding only in stressed states and non-bank financial institutions (NBFIs) operate outside the capital regime. The paper’s core result is that NBFIs can amplify the contractionary effects of monetary policy, mainly via the asset price channel, with the amplification strongest in the left tail of the GDP distribution and still pronounced under zero lower bound conditions. The model introduces asymmetric, state-dependent capital adjustment costs that activate only when a bank’s capital ratio falls below a threshold, making loan-deposit spreads sensitive to capital shortfalls but not to surpluses. In the NBFI sector, tighter monetary policy reduces the market value of bonds held by NBFIs, eroding their net worth and lending capacity and limiting their ability to offset reduced bank credit, which increases downside GDP-at-risk. The paper contrasts these short-run vulnerabilities with a long-run trade-off: a greater share of NBFI lending is associated with higher welfare in the model. As a staff working paper, it is published to elicit comments and debate and does not represent Bank of England policy.