Following speculation that Chief Executive Officer Steve Jobs is sick again after successful cancer surgery in 2004, Apple Inc. said Jobs has no plans to leave the company and that his health is "a private matter." The shares fell 10 percent.

"Steve loves Apple," finance chief Peter Oppenheimer said when asked about Jobs' health on a conference call today. "He serves as CEO at the pleasure of the board. He has no plans to leave Apple. Steve's health is a private matter."

Since Jobs, 53, took the stage in San Francisco last month to introduce the newest iPhone, speculation among attendees and bloggers has run rampant that he may be sick again after successful surgery for a form of pancreatic cancer in August 2004.

If Jobs were to leave for any reason, the stock would plummet 25 percent, said Gene Munster of Piper Jaffray & Co. That would erase about $36 billion in Cupertino, Calif.-based Apple's market value.

The company, maker of the best-selling iPod media player, the Macintosh computer and the iPhone handset, depends on Jobs for his fashion sense and technology savvy.

Apple spokeswoman Katie Cotton said after the event Jobs was suffering from a "common bug" and was taking antibiotics.

Jobs, who co-founded Apple in 1976 with Steve Wozniak and returned as chief in 1997, may be more closely linked to the company's prospects than any other CEO.

He revived sales of Apple's flagship Macintosh, the personal computer that accounts for almost half of revenue. He conquered the digital music industry with the iPod and last year led the company into the mobile-phone market with the iPhone.

Under Jobs, profit jumped to almost $3.5 billion last year as sales topped $20 billion for the first time. Apple's stock surged from less than $10 in 1997.

Yesterday, however, its stock dropped $16.59 to $149.70 in late trading, extending a decline that began when the company gave a disappointing forecast after the market closed.

Apple forecast fourth-quarter profit below analysts' estimates, signaling that back-to-school orders and demand for the iPhone may not maintain the company's growth streak.

Earnings for the July-to-September period will be about $1 a share, compared with $1.01 a year earlier, Apple said yesterday in a statement. Sales will climb to about $7.8 billion. Analysts in a Bloomberg survey had anticipated $1.24 a share and $8.3 billion.

The forecast raises concern that the U.S. economy may eat into surging sales of the iPod, iPhone and Mac computers. Back-to-school promotions and costs to introduce new products may reduce profit as well.

While Apple typically beats its own projections, the report follows signs from Microsoft Corp. and Google Inc. that customers are curbing technology spending.

Apple also yesterday reported third-quarter net income climbed 31 percent to $1.07 billion, or $1.19 a share, from $818 million, or 92 cents, a year earlier, Apple said in the statement. Sales rose 38 percent to $7.46 billion, topping analysts' estimates of $7.36 billion.