If there is any apparent reason of this pump then I can't seem to see it . However ... I'd say that the price won't reach 500$ in the next two weeks (before the end of December) but there is chances that we will start the new year with 500$++ within the first couple of weeks of January , price should continue to rise slowly and we may see pump when we are too close from the halving block reward date . (Let's say June) .