On first day of the Tim Cook era, Apple's shares actually outperformed the market
Fast-forward to Wednesday. Jobs submits his resignation, the market digests the news overnight, and on Thursday Apple loses 0.65% -- which on a day that the Dow and the S&P 500 fell 1.51% and 1.52%, respectively, is almost like going up.
It helps that Jobs will be sticking around as chairman of the board, even if he's no longer CEO.
But you should probably think of what happened Wednesday as just one step in a carefully choreographed dance in which Jobs parcels out details about his medical condition, takes a series of increasing extensive medical leaves, shares more and more stage time with his senior staff, and passes the torch to his successors one title at a time.
Result: By the time Tim Cook became CEO Wednesday, the Street actually seemed relieved.