Ridiculous reading this thread and seeing one reasonable answer dismissed in favour of one that lays the "blame" elsewhere. Markets are driven just as much by perceptions and sentiment as they are by fact.
I am sensing far more negative sentiment towards Apple online. Personally I am also reading of a few Apple loyalists who are making a switch to other phones. We suddenly have other tablets being considered by many, not just iPads. Then you read news of another smartphone outselling Apple. This affects the buying decision of some. These things affect shareholder sentiment.
My comments in this thread aren't here to discredit what others are saying, because BeVonk! is right, i'm just adding some extra detail to the discussion. As BeVonk! pointed out, it's a combination of things.
What you are seeing at the moment, because of uncertainty in the market, is capital moving from risky assets to safer assets. Apple, by nature, being so dependant on the next product cycle is seen as a risky investment because everyone realises a real stinker on the next product cycle would heavily affect the stock price in the short term. So money is always very twitchy, with everyone watching to spot the next dip before it happens so they can get out and then back in at a lower price. If anything, it just makes it a great stock to trade because you get actual movement. Movement is where money is made. As soon as it's obvious the stock has bottomed out you will see big money buying it up again because the fundamentals are still very strong. In the same way that Apple's small product offering creates nervousness because of the importance of the next iteration, it's small size also gives them a huge advantage because they can respond quickly to mistakes.
I'm really happy there is some pressure on them now(some deserved, some plain old schadenfreude) because it'll force them to include a bit more bang in each product release. The big picture problem Apple execs always have to think about is what they going to release over the next 5 years. It's about finding the perfect balance between including enough innovation to excite people and not too much that they run out of improvements they can actually implement. Samsung are going to face a similar problem within the next 3 product cycles, because they can't play the screen size card again and android is becoming feature complete. Once all their phones have 1080P displays what then? People are going to start to feel their phones are good enough causing them to not upgrade as often.
The bet Apple made in not changing the look of the iphone for 3 generations was perhaps a bit of a mistake, and came across as not trying hard enough considering the competition from Samsung. Apple needs to do two things to get back the gloss they seems to be losing: they need to give the iphone a new look, and they need to revamp IOS because it has been getting a bit stale lately. Just those two thing will send sales through the roof. It would also help to offer a range of screen sizes.
If you look at the rest of their product offering - it's steller. The Imac, Macbook Pro, Macbook Air, and Macbook Pro Retina are all class leading.
Another positive change people don't really consider is Apple's decision to move OSX to a yearly release cycle. That could be an advantage over Microsoft because it'll allow them to shift quicker.
So ja, people are going to make a lot of money when Apple's stock bottoms out.