It's already happening: http://www.bloomberg.com/news/2013-09-17/less-tapering-becomes-tightening-credit-no-matter-what-fed-says.html http://www.bloomberg.com/n

It's already happening: http://www.bloomberg.com/news/2013-09-17/less-tapering-becomes-tightening-credit-no-matter-what-fed-says.html http://www.bloomberg.com/news/2013-09-17/less-tapering-becom... Considering that for a period of time it was practically free to borrow money (interest rate < inflation), I don't think it's that unreasonable to describe that as "unsustainable".