LOS ANGELES AND SAN FRANCISCO — The decision by Apple Inc. boss Steve Jobs to take a medical leave after learning that his health issues were "more complex" than originally thought renews questions about the succession plan of a company whose fate has been closely linked to its charismatic leader.
On Wednesday, only a week after assuring investors that he felt fit to lead the Silicon Valley giant, Jobs wrote in an e-mail to employees that he would pass day-to-day management duties to Tim Cook, Apple's chief operating officer, until the end of June.
Cook will reprise the role he played in 2004, when Jobs underwent surgery to remove a cancerous tumor from his pancreas.
"Steve Jobs is simply not going to be the force in the company that he has been in the past," said Boston University management professor James Post. "What we are really seeing is another step taken toward the next generation of leadership at Apple."
Jobs has not said whether his cancer has returned, only that he is suffering from a hormone imbalance that caused him to lose weight at an alarming rate.
Some investors questioned whether Apple had been forthcoming enough about the health of its chief executive -- a murky area of securities law.
The shares of the Cupertino, Calif., company tumbled more than 7% to $79.30 in after-hours trading Wednesday after the release of Jobs' e-mail. They had fallen nearly 3% to $85.33 before the news.
Apple's stock has been buffeted by rumors about Jobs' health since he appeared gaunt at a developers conference in June. Gossip swirled anew last month, after Apple said he wouldn't deliver the keynote address at the Macworld Conference & Expo for the first time in 11 years.
In an effort to quell the speculation, Jobs, 53, disclosed the hormone imbalance Jan. 5 and said he was working with doctors to correct it.
"I will be the first one to step up and tell our board of directors if I can no longer continue to fulfill my duties as Apple's CEO," Jobs said then.
But he said Wednesday that his health issues were "more complex" than thought and that curiosity over his condition continued to be a distraction, not only for him and his family but also for everyone at the company.
"In order to take myself out of the limelight and focus on my health, and to allow everyone at Apple to focus on delivering extraordinary products, I have decided to take a medical leave of absence," Jobs wrote, adding that he planned to remain involved in strategic decisions during his absence.
