Watching the Apple share price graph over the course of 7 days starting with Steve's step down announcement yesterday through the earnings call today is going to be a really interesting exercise on timing bad news.
Word on the street is that Jobs had already shown up less at Apple in the last few weeks, the announcement was obviously timed to coincide with a bank holiday.
But, if Apple's quarterly results turned out lower than Apple's guidance and the Street's expectations, I bet Jobs' sick leave would have been announced at an earlier date, so that the two shocks wouldn't have amplified one another.
(Instead, at today's closing bell Apple's stock was back to the level of a couple days a go. An hour later, when Apple's Q1 results were in, trading actually went up to an unprecedented height. So Apple's cunning plan worked out quite nicely.)
But on a more fine grained timescale a few days more or less in the timing of the announcements might make quite a difference in how people perceive this. If they had announced a month ago instead of right next to record quarterly earnings it might have hurt the stock more at the time than it does today.
The market is in theory 'efficient', but in the short term it tends to overreact to bad news, so combining bad news with extremely good news may be a viable method to offset the effect of the bad news on the stock.
Savvy investors will have priced Steve Jobs health in to their stock holdings already, those that are on edge might panic and sell unless there was a second factor.