During the last 2 days of this year, approximately a quarter of a million homes in the homebuilder's previously stagnant inventory were placed under contract in 'all cash' transactions. Yeah, right. That would be the only legitimate explanation for upward movement in homebuilder stock prices.
A similar question: why would a herd of sheep suddenly migrate in its pasture from the west toward the east. Possible answer: a few edgy sheep believe they hear bushes rustling on the west perimeter and therefore take a few steps eastward. Other sheep see this eastward movement of their peers and move likewise -- either from habit or believing there must be a reason. This phenomena multiplies. Much of the herd is simply pushed eastward by the rest, whether they want to go or not--without any reason.