Apple stock was down 8% today following disappointing iPhone sales numbers for the final quarter of 2013.

Even though Apple sold a record 51 million iPhones last quarter, the number was lower than Wall Street analysts were expecting. Most thought Apple would sell 55 or 56 million iPhones. Meanwhile, Carl Icahn tweeted today that he just bought another $500 million in Apple stock. That didn't help the price though. It's still down.

Here's a look at Apple's stock after the closing bell:

CNBC

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