PLS chart, page-11618

well, fundamentally:
Stock SP movement isn't dictated by fundamentals.
Stock SP is grand sum of all knowledge and ignorance at any given moment in time.
In other words: SP is reflection of sentiment and emotions not fundamental value of company (of which chart is illustration).
Therefore: stock will move in the path of least resistance regardless of fundamentals.
If shorts feel they can capitalise on grand sum of knowledge and ignorance = they will go for it. If not = they'll switch in other direction.
Market is just one big herd moving in direction of least resistance and can be corralled just like cattle.

Over longer period: fundamentals will reflect fundamental value of company. But SP will rarely reflect true fundamental value of company. It will either be under or overvalued at any given time, depending on current market sentiment.

So in short:
Why? Because market is neither rational nor reflective of true value but a herd running through a fence.