Steve Jobs's successor as chief executive faces one of the toughest challenges in corporate history

Apple 's new chief Tim Cook, Apple vowed to stick' s "unique principles and values ??\", as investors marked his first day as the successor of founder Steve Jobs with the sale of shares and marking the company 's value by more than 5% or around £ 10 billion.

With the acquisition of jobs that are widely regarded as a genius, the world as breakthrough products considered as the iPod and iPhone, faces cook one of the biggest challenges in the company's history, as he strives to maintain Apple 's position as the world' s especially technology companies. Earlier this month, Apple adopted shortly, the oil behemoth Exxon \ the world's most valuable company in just 14 years after flirting with bankruptcy.

In a company-wide e-mail on Thursday, said Cook, who was at Apple for 13 years, the staff: "I want you to be sure that Apple will not change, I appreciate and celebrate Apple 's unique principles and . Steve built a company values ??and culture like no other in the world and we will remain faithful to that -. it is in our DNA, we continue the best products in the world that delight our customers and do. our Staff very proud of what they do. "

The first challenge for Cook 's rule, the expected unveiling of the next versions of its iPhone, widely expected within the next six weeks as Apple wants its leading position in the mobile phone industry, where it from nothingness to increased capitalized with the largest Revenue and profit in nearly five years. In the computer market, still have their little revenue grew faster than the rest of the Windows-based market for 20 consecutive quarters. IPad tablet and its still dominates the rapidly growing market, despite competition from dozens of competitors with Google 's free Android operating system.

Reports say that Jobs spent his last day as chief executive at the Apple campus in Cupertino, California, where he was a full day, and that he intends, a "active" Chairman of the company.

Although he gave no reason for his departure, announced late on Wednesday, medical observers believe it is linked to the rare neuroendocrine cancer for which he was treated in 2004, and the liver transplant he received in April 2009.

Cook, 50, was until Wednesday, the company 's Chief Operating Officer, and was acting CEO since January. He has been seen for a long time as the natural successor.

But even as investors in the sale of shares - it is recovered to be down only 1.1% - were business analysts that Cook had at least two years, which rely on products to indicate that Apple has been in development.

The departure of Jobs, the visionary who has set out Apple's philosophy for decades - first between 1975 and 1985, and then from 1997 to this year - had been seen by some investors as cause for alarm at the company, which is now more valuable than rivals such as Microsoft, Dell and Intel.

But Gartner Research analyst Michael Gartenberg suggested that customers continue to be loyal to the brand. Without jobs, he believes the company 's challenge is the same as it was with him, continue to explore options to procure the bar with entertainment.

"Yes, is the transition for some ... but it does not mean 't, Apple itself is going to change fundamentally," he said. "Sure, Apple 's competition would be foolish to believe this is a situation that they might somehow benefit to \."

Richard Windsor of Nomura said: "by its own account, Apple 's pipeline for several years, so when to stop innovation dead of night it would still be some time before the effect was felt heard that said, the the introduction. next iPhone already delayed the expected worldwide in July is now more important than it already was. If the hardware is not impressive ... then the company can be seen that to lose momentum. \ be "

Richard Gardner of Citigroup advised investors buy the stock if it goes down, Jobs said had laid a strong foundation, and that he expected to win market share for years. "From our perspective, [Cook] is a tough but well-regarded leader who will continue to keep Apple employees to an extremely high standard," he wrote. "

The quiet man with similar objectives

Steve Jobs is known for his temper described, while Tim Cook is a soft-spoken. California Jobs is a new era known for his interest in vegetarianism and spirituality, but Cook, who is from Alabama who loves football. And while jobs enjoyed rock star-like fame, the intensely private cooking wonk for years in secret, an operations center, which labored to make the proverbial trains on time.

But now it can be to cook the things that stocks with jobs that are most important, as he takes over as head of one of the world 's coolest companies. One such feature is sheer competitiveness. "He 's not in it for the fame or the ego or the money. It' s in it to win," said Greg Petsch, his boss at Compaq Computer in the late 90s.

"The guy is a phenomenal operating system executive," said Mark Briggs, chef 's chief at Intelligent Electronics from 1994 to 1997 was. Briggs, remembers a very analytical executive, on metrics that the company 's Supply Chain focuses on outdated. "He just works all the time, that 's life \."

Cook has a strong balance sheet as a stand-in. When Jobs was sick, first in 2004, Koch took over and it went so well he was Chief Operating Officer. In his second stint, got Apple 's warehouse 62%.

Charles Arthur and agencies