Shares of Apple Inc. tumbled as much as 7 percent on Thursday as investors targeted the high-flying stock in a general U.S. market slide prompted by credit fears.

Apple shares have gained about 34 percent since the start of the year, largely buoyed by expectations for the company's media-playing iPhone that was unveiled in January and hit store shelves in June. In that time, the S&P 500 Index has shed about 2.6 percent.

The stock's been a huge outperformer, and I think it's just (investors) taking some profits, said American Technology Research analyst Shaw Wu. It's probably one of the few names people have made a lot of money on.

We really haven't picked up anything company-specific, he added.

Bear Stearns analyst Andrew Neff, in a generally upbeat note over Apple's prospects, cited as one concern for the company the possibility that growth rates may have peaked and could slow, which can hurt a stock's P/E multiple.

But Neff maintained his estimates for the company and kept an outperform rating on the stock.

Apple shares fell 5.2 percent to $113.63 in afternoon trading on the Nasdaq after falling as low as $111.62 earlier in the session.

(Reporting by Robert MacMillan)