Is it more accurate to refer to QE∞ instead of QE3? Unlike the previous doses of US QE, this campaign of asset purchases has no official limit, and will carry on until the unemployment rate has improved “substantially” – a word that the Federal Reserve can define, and redefine, as it sees fit over the years ahead.

I have already argued that this should be regarded as stunningly aggressive. In the latest Note video, Gavyn Davies, a fellow FT blogger, agrees. The key point, he suggests, is that over the last year the Fed’s reaction function has changed. It is not just that the employment situation has worsened but also that, for whatever reason, it has decided to give the full employment part of its mandate greater emphasis than before. There are plenty of possible reasons for this, which we discuss in the video: Read more