The bankers are all sighing with relief. It looks like they weathered yet another fit in the markets.
Is there a “Yellen put” in place? Yes. But more accurately it is a “Federal Reserve put.” It’s been around for quite a while. We don’t have real prices. We don’t have a real market.
Also one thing which is not really discussed often in depth is the degree to which the petrodollar plays into all of this. Oil goes down in price, the dollar typically goes higher (and vice versa, also oil is priced in dollars on the world market) and lower fuel prices juice the American economy. It may be that fracking, and the oil supply it has created (along with a Saudi Arabia which has turned on the spigots, likely to hammer the economies of Russia and Iran who are both hurt by a Saudi created glut) is actually the most important “monetary” tool right now.