Updated from Aug. 24 with premarket quotes for Thursday

CUPERTINO, Calif. (

TheStreet

) --

Apple

(AAPL) - Get Report

shares tumbled in premarket trading on Thursday after iconic CEO Steve Jobs

handed in his resignation

.

Investors responded negatively to the departure of Apple's innovator-in-chief. Within a couple of hours of the announcement Wednesday, the company's stock was down $19.08, or 5.07%, to $375.10.

In premarket trading Thursday, the stock was slumping further, down almost 5% to $358.

Apple's stock tumbled on news of Steve Jobs' departure.

Part CEO, part cultural icon, Jobs is widely credited with saving the company during the 1990s and has played a pivotal role in the development of category-leading products like the iPod, iPhone and iPad.

Jobs' exit from the Apple hotseat, however, is not completely out of the blue. The Apple chief announced

his third medical leave of absence

from the company in January, handing day-to-day running to COO Tim Cook.

Cook,

Apple's obvious heir apparent

, has proved an extremely able stand-in CEO, successfully running the company during his mentor's absences.

Apple recently reported blowout

third-quarter numbers

, buoyed by stellar iPhone and iPad sales. The tech bellwether, which briefly surpassed

Exxon Mobil

(AAPL) - Get Report

to become the

world's most valuable company

earlier this month, is also expected to launched a new iPhone during the coming weeks.

TheStreet's

Jim Cramer, speaking on

CNBC

said that investors should not lose faith in Apple, even without Steve Jobs at the helm. "The fear is misplaced because of how strong that bench is," he said. "I think

Apple is a terrific company."

--

Written by James Rogers in New York

.

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