Quantitative easing
A central bank buying bonds with money it creates, in order to push long rates down once the short rate is already at zero.
How to read the number
It works through the price of long debt: bonds get dearer, their yields fall, and borrowing becomes cheaper for everybody else.
When the metric lies
The side effect is that financial assets appreciate sooner and more visibly than the real economy recovers.
Also known as: asset purchase programme