Most generally its a supply demand type of thing. People get all confused and they think that stocks are an actual representation of the underlying company, when in fact thats only a small part of it. A good analogy is that a stock is a commodity that has some relationship to the underlying equity as well as the market in generall and any number of other things. Also a general comment. When people say more buyers than sellers, generally thats not the case, because for every transaction someone is on the opposite side of it. A better analogy is to say the buyers are currently much more aggressive than the sellers.
In any case, we are dealing with, IMHO, a sold out market. Will see what happens when earnings start to come in, that will give us a much more clear picture of what is going on.