Quantitative easing (QE) is a monetary policy used by central banks to increase the money supply by buying financial assets from banks and others. It involves the central bank electronically creating new money, then using that money to buy bonds or other financial assets, increasing the money supply and lowering interest rates. The goals are to stimulate the economy and prevent deflation. Risks include higher inflation if overused or not being effective enough to stimulate lending and growth. It has been used in Japan, the US, and UK in response to economic crises.