Staff Working Papers 20 December 2019 Staff working papers describe research in progress by Bank staff and are published to elicit comments and to further debate. The following Bank of England staff working papers have been published today: Monetary policy and birth rates: the effect of mortgage rate pass-through on fertility By Fergus Cumming and Lisa Dettling The role of households’ borrowing constraints in the transmission of monetary policy By Fergus Cumming and Paul Hubert UK house prices and three decades of decline in the risk‑free real interest rate By David Miles and Victoria Monro Simulating liquidity stress in the derivatives market By Marco Bardoscia, Gerardo Ferrara, Nicholas Vause and Michael Yoganayagam Platform competition and incumbency advantage under heterogeneous switching cost — exploring the impact of data portability By Paolo Siciliani and Emanuele Giovannetti Capital and liquidity interaction in banking By Jonathan Acosta-Smith, Guillaume Arnould, Kristoffer Milonas and Quynh-Anh Vo Macroeconomic effects of political risk shocks By Sinem Hacioglu Hoke The empirics of granular origins: some challenges and solutions with an application to the UK By Nikola Dacic and Marko Melolinna All you need is cash: corporate cash holdings and investment after the financial crisis By Andreas Joseph, Christiane Kneer, Neeltje van Horen and Jumana Saleheen