Apple stock reacted in after-hours trading by dropping more than 7% to just above US$79, its lowest level since November 2006. In regular trading earlier, the stock was off 2.7%, to $85.33.

Analysts were surprised by the move, if only because Jobs' Jan. 5 public announcement . "I certainly didn't expect the two to come so close together," said , an analyst with

"I was a little surprised," agreed Van Baker, an analyst with Gartner Inc. "But I don't think there's any subterfuge or deception here. Clearly [Jobs' health] is a moving target, and after interacting with his doctors, [he] decided that it was more complicated than he thought."

The impact of his absence may be minor, said both Gottheil and Baker -- if Jobs is out for only a few months. If he is unable to return on time, or resume his post as CEO, however, Apple's future is more difficult to predict.

"I don't think that there will be any changes visible in that period of time," said Gottheil, talking about the time between today and the end of June. "Apple can clearly execute, so if Jobs is able to do what he says and come back in June full bore, the effect will be zero."