I was thinking last night about the question "who is buying?" and I wonder if it's the wrong question.
It seems to me that in order to move so far on unexceptional volume, there must be a lack of market making and/or swing trading type activities that act as virtual limit orders. That to me makes total sense - this last year has been the most trending market I've ever seen, so on balance everyone adopting countertrending strategies must have gotten their teeth kicked in both going down and going up. If they, as a result, reduced their size or abandoned their countertrending strategy (which seems rational) then presumably it's now easier to move the market on low volume.
The interesting thing about this is that it seems like positive feedback loop - the more trending we see, the more the countertrenders lose. And the more they lose, the easier it is to trend.
Anyone want to explain why this is wrong, or if it's right what negative feedback mechanism eventually puts a stop to it? If the trend was down, I suppose pure fundamentals buying would eventually produce a floor. But when the trend is up, I don't see any analogous force.