Apple Inc. shares dropped as much as 7 percent in after hours trading following news of the resignation of the company's co-founder and chief executive officer Steve Jobs.

On Wednesday, Jobs told the Apple board of directors and the Apple community he could no longer meet the “duties and expectations” of the position. Jobs had battled pancreatic cancer since 2003 and received a liver transplant in 2009. He has been on medical leave since January.

Apple said in a statement Jobs had “saved” Apple with “extraordinary vision and leadership.” The company said Jobs has been elected as chairman of the board of directors and will, in that role, continue to contribute “unique insights, creativity and inspiration.”

The statement said Tim Cook will take over as Apple's new top executive at the recommendation of Jobs. Cook had previously served as the company's chief operations officer. Apple's board said Cook has worked for 13 years at Apple and demonstrated “remarkable talent and sound judgment in everything he does.”

Apple is now the world's most valuable technology company, but in the 1990s, the company nearly went bankrupt. Its fortunes were transformed when it shifted its focus away from being a personal computer manufacturer into a company producing the trendy iPhone and the iPad tablet for audio-visual media.