Definition
A monetary policy tool where the central bank buys financial assets to inject reserves and lower long-term interest rates.
During QE, the Fed creates new bank reserves to purchase Treasury bonds and mortgage-backed securities from the open market. This increases the money supply, lowers yields, and pushes investors toward riskier assets (the "portfolio balance effect"). Major QE programs: QE1 (2008-2010), QE2 (2010-2011), QE3 (2012-2014), and COVID QE (2020-2022, the largest at ~$4.6T).