Apple posted quarterly results that beat estimates Monday, but reported weak iPhone sales and handed in a current-quarter revenue forecast that underwhelmed, sending shares lower in extended-hours trading.
The company posted earnings of $14.50 a share on sales of $57.59 billion, surpassing expectations for $14.07 a share on sales of $57.46 billion, according to a consensus estimate from Thomson Reuters.
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During the quarter, Apple said it sold 51 million iPhones, fewer than the 55-million estimate expected by Wall Street analysts. Additionally, the company sold 26 million iPads and 4.8 million Macs.
In addition, the company said it expects to hand in current-quarter revenue of between $42 billion and $44 billion, versus expectations for $46.05 billion.
Meanwhile, Apple CFO Peter Oppenheimer said the company's iPad sales in mainland China more than doubled during the holiday quarter and saw strong growth in emerging markets like Latin America and Russia.
"We generated $22.7 billion in cash flow from operations and returned an additional $7.7 billion in cash to shareholders through dividends and share repurchases during the December quarter, bringing cumulative payments under our capital return program to over $43 billion," Oppenheimer said in the company's press release.
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BGC downgraded the stock to "hold" from "buy" on Monday, noting that shares have hit the brokerage's existing $550 price target.
Last week, the Wall Street Journal reported that Apple is planning on releasing two new iPhones with larger screens. Citing sources, the WSJ said one model will have a 4.5-inch display and the other will have a 5-inch display. Both phones are expected to have metal casings and will not have a curved display.
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Meanwhile, billionaire investor Carl Icahn most recently said he has raised his stake in Apple to $3 billion, and took to Twitter to criticize the company's board. Icahn has been adding pressure on the company to boost its share-buyback program. Icahn also said he was planning to unveil another major stake in a new company over the next few weeks, likely on Twitter.
And earlier this month, Apple and China Mobile struck a long-awaited deal for the Chinese mobile carrier to launch the iPhone across the country next month. Apple CEO Tim Cook called the deal a "watershed" moment, referring to China Mobile as a great cellphone firm with a "very fast network."
(Read more: Biggest loser of Apple-China Mobile deal: Samsung)
—By CNBC's JeeYeon Park. Follow her on Twitter@JeeYeonParkCNBC