Or maybe it's one big hedge fund unwinding it's position. Obviously it's that manager or managers position that Apple is overpriced. With the way the market is roaring there would be no need for a fund to be liquidating. If anything money should be pouring into funds.
If you actually take time to read the articles you will see that some funds sold shares numbering from a few 10's of thousands to a couple hundred thousand. Another article says Einhorns' fund bought over a million more. Balancing the reports shows a fund buying INCREASE in holdings.
I would suspect this is due less to one guy sitting around scratching his head saying "Hmmm, this looks overvalued all of a sudden, better dump all my shares" and more due to computers and high frequency trading. But maybe my view of what really goes on is as wrong and simple as yours.