Apple reported its quarterly results on Tuesday, July 24, delivering a rare disappointment with lower-than-expected iPhone sales. The announcement sent the company's stock down 5 percent in after-hours trading.

The disappointing figures on Tuesday marked only the second time in 39 quarters Apple reported results that missed analysts' profit and revenue expectations. The first time the company posted disappointing results was for its quarter ended Sept. 2011. The new results come among signs that sales of the world's most popular smartphone have started to slump this year. Apple sold 26 million iPhones in the quarter ended June 30, a 28 percent increase compared to the same period a year ago, but a decline from the 35.1 million sold in the previous quarter this year.

The decline is widely believed to be caused by the high anticipation for the next-generation iPhone, expected in October, as consumers hold out for the new model. Apple also noted the sluggish European economy is affecting results there. Heightening economic concerns even further, other closely watched companies reported more sluggish results Tuesday as well. United Parcel Service (UPS) cut its profit forecast for the year in light of a poor economic outlook, while Neflix warned of an imminent quarterly loss and said it might not meet its subscriber-growth targets.

Meanwhile, Apple's disappointing results highlight just how much the company relies on blockbuster products. The iPhone is the company's biggest revenue generator, and if sales of the smartphone slump, the entire company is dramatically affected. According to industry watchers, the iPhone is not necessarily in trouble, but consumers are waiting for the new iPhone model expected this fall, repeating the pattern of past years.

"Our weekly iPhone sales continue to be impacted by rumors and speculation regarding new products," said Apple CFO Peter Oppenheimer. Apple launched its latest smartphone model, the iPhone 4S, last October, and the company is expected to follow the same release schedule with the new-generation iPhone this year. Oppenheimer also mentioned the weak European economy having an impact on sales, but the company did not experience "obvious economic issue(s)" in the United States or China, added Apple CEO Tim Cook.

Sales in emerging markets, however, generated less momentum than expected. One of the company's hottest markets is Mainland China, where iPhone sales have more than doubled in the quarter from a year ago, but declined from a fivefold increase the previous quarter. According to Cook, half of the sequential decline of $2.2 billion in China sales was caused by a previous buildup in channel inventory that resulted in lower sales into the channel this quarter. The CEO also added that normal "seasonality" after a large product launch affected China iPhone sales as well.

The slump in iPhone sales also affected the company's growth markedly from its previous quarter. Apple reported a 22.6 percent increase in revenue to $35 billion from a year earlier, but that 22.6 percent increase was down from 59 percent in the previous quarter. Profit rose 20.7 percent to $8.8 billion - $9.32 a share - from the previous year, but was down from the 94 percent growth the previous quarter. According to Thomson Reuters, analysts were expecting revenue of roughly $37.2 billion and earnings of $10.37 a share.

The Cupertino, California-based tech giant said it expects fourth-quarter earnings of $7.65 a share on revenue of roughly $34 billion. Analysts polled by Thomson Reuters predicted a profit of $10.23 a share on $38 billion in revenue. Apple ended the June quarter with $117.2 billion in cash, compared to $110.2 billion at the end of its second quarter. The company also said it would pay its $2.65 a share dividend on Aug. 16.

Following the disappointing earnings results on Tuesday, Apple's shares tumbled 5.4 percent to $568.80 in after-hours trading. The stock was down 0.5 percent at $600.92 at 4 p.m.