What is quantitative easing?
Usually, central banks try to raise the amount of lending and activity in the economy indirectly, by cutting interest rates.
Lower interest rates encourage people to spend, not save. But when interest rates can go no lower, a central bank's only option is to pump money into the economy directly. That is quantitative easing (QE).
The way the central bank does this is by buying assets - usually government bonds - using money it has simply created out of thin air.
The institutions selling those bonds (either commercial banks or other financial businesses such as insurance companies) will then have "new" money in their accounts, which then boosts the money supply.
http://www.bbc.com/news/business-15198789