You seem to be talking at cross purposes. Maybe I can help, it being the season of goodwill and all.
pbracken seems to be talking about innate/intrinsic/true value, the other posters about market valuation.
Market valuation is of course almost entirely determined by demand and supply for a company's shares, modified slightly in the case of MM stocks.
Innate/intrinsic/true value has nothing to with demand/supply for the shares.
The difference between the two is the main way in which trading opportunities, both long and short, arise.