How does the US's QE programme work?
13 June 2013 Last updated at 06:49 BST
Global markets have been shaken in recent weeks by concerns that the US Federal Reserve may begin scaling back its stimulus programme.
The Fed is pumping $85bn (£54bn) a month into the economy, in a programme of quantitative easing (QE).
But what is QE exactly?
Sharanjit Leyl asked Nobel Prize winning economist Thomas Sargent about the mechanics of QE and what the impact may be.