In an article we put out one month ago on 11/7 (AAPL Bear Markets: Is a '4' Handle in the Cards?), we looked at prior 20%+ declines in AAPL stock and found that based on the 'average' decline, a downside base-case scenario for AAPL would be a 30% decline over a period of 81 calendar days.
The table below is updated from the original article. Using those 'average' declines would imply a downside target in AAPL of 489.40 on or around December 8th. After the declines of the recent days, AAPL is currently close to its average declines in terms of both time and price. Given the hysteria over the stock's recent decline, it is hard to believe that the current decline has been nothing more than a run of the mill decline.