If you actually believe that it's "artificial", then sure. There are hundreds of billions of dollars looking for situations like this, if the money managers actually believed the absurd conspiracy theories. Many HN visitors seems foolishly naive in the belief that a couple of players make the market (clearly because they have a personal interest. Never before have I seen such an interest in the stock market, or this feeling of profound victimization because it doesn't always move in one direction), when there are tens of thousands of very large players in the market, all of which want to screw every other player to the greatest extent possible.

If AAPL were underpriced, there would be enormous buy pressure to the point that it is no longer underpriced.

(Sidenote: Among one of the loudest proponents of the conspiracy theory is John Gruber, who today proclaimed that $500 proved it. Only the article he linked actually said $550. It turns out that there are psychological pivot points that are often hit nearing close. The market is made by people, and people understand and gravitate to emotional numbers)