It's more that Apple's stock behaves in completely irrational ways; typically, news which would cause any other company's stock to skyrocket instead causes Apple's to plummet. In the past, "analysts" such as Jim Cramer have admitted to deliberately manipulating the market to produce this effect, which may provide some explanation, but there seems to be a consistent trend of underestimating/undervaluing Apple regardless of how many consecutive quarters of stellar performance they crank out.
Really? You think you know when the market is being irrational? Can I ask how much money you've made trading your knowledge so far? I assume you're invested in Apple, since you know that the market consistently underestimates them.
Philip Elmer-Dewitt of Fortune (if you'd like some reading on the subject) does a rather amusing quarterly piece in which he compares analyst predictions of Apple's performance with observed reality. If it happened once or twice, that would be understandable; such predictions are complex and difficult to make. But the track record is so consistently and so universally bad that I find it difficult to believe there's a truly rational process behind it; sooner or later, folks should be noticing the disparity between prediction and reality and trying to fix their process.
Apple's stock price seems to behave similarly; if any company not named "Apple, Inc." announces a new product which receives good reviews, generates high pre-sale demand and looks to have a high profit margin, that company's stock price quite predictably rises. But if the company happens to be named "Apple, Inc." the stock price almost invariably drops (go look at charts for AAPL on and around the days of major product announcements and launches). Perhaps you're aware of some deep principle which explains why this is rational behavior on the part of investors and traders, but I certainly am not.
Um, if a person claims that the market itself is behaving irrationally then how why would you expect that they could prove it by making money on said market?
You know what's interesting about the stock market? If everyone else is wrong and you're right: you lose.
It's not irrational. The traders essentially control the stock market and call the shots by manipulating the market into a favorable position then sell the stock. A glut of shares appearing on the market would thus drive the price down. The term is called "profit taking".
According to your conspiracy theory, the price is sometimes artificially low and sometimes artificially high. Why haven't you made a profit by short selling? Why wouldn't a competing company?