VOX  CEPR Policy Portal

Central banks have resorted to various unconventional monetary policy tools since the onset of the Global Crisis. This column focuses on the macroeconomic effects of the Federal Reserve’s large-scale purchases of mortgage-backed securities – in particular, through reducing the ‘mortgage spread’ between interest rates on mortgages and government bonds at a given maturity. Although large-scale asset purchases are found to have substantial macroeconomic effects, they may not necessarily be the best policy tool at the zero lower bound.