Apple's stock is tumbling in after-hours trading onnews that Steve Jobs is resigning as head of the company. After closing at $376.18, Apple stock has fallen 5 percent to $357.02 as of 7:59ET, according to NASDAQ.

Jobs, who cited an inability to meet his "duties and expectations as Apple's CEO" as the reason for his stepping down after 14 years, continues to battle a form of pancreatic cancer more treatable than other forms of the disease.

He will replaced by Chief Operating Officer Tim Cook. Many analysts say Jobs, who was last year named "World's Most Valuable CEO" by Barron's, leaves a fundamentally-sound company able to survive without him at the helm.

"The real takeaway is not to underestimate the bench," Kevin Dede, an analyst at Brigantine Advisors, told Reuters. "He's got an amazing cast supporting the operation of the company."

Cook, who has served as COO since 2004, is "highly regarded" inside apple, Ashok Kumar, an analyst at Rodman & Renshaw LLC also told Reuters. "From a succession perspective they could not possibly identify a better candidate."

Cook has already served in the role of interim CEO multiple times over the course of Jobs' battle with cancer, and the effect on stock prices has been mixed. On January 17, when Apple's board of directors last granted Jobs a leave of absence, Apple's stock dipped 6.2 percent to $326.72 on January 21 from $348.48 on J..., before again rising.

Still, even as stocks dropped, analysts expressed confidence in Cook's abilities to lead the company with Jobs.