I’ve been attacking this one from another angle, trying to understand what the big institutions are doing. It seems to me that the key is TTM PE.

Look at the URL below. Prior to the 2008 crash, AAPL was trading with a 30 PE, spiking up into the 40s, and then went south with the rest of the market, falling to 12 or so. Since then, it has rapidly gone back to a tight range of approx 18 to 23 TTM PE. That is, take the PPS range between each earnings, and apply TTM PE and you’ll see that for the last 4 quarters this range has held.

Last earnings it climbed in a straight line for weeks before, only to sell off the next day. The PE range held. For the sake of argument, let’s say big funds are using the simple rule to load up every time the PE dips below say 19, hold until 22, and then start unloading at 23. Does this insight give us a “floor” below which the PPS won’t fall? I’ll let you do the maths, as you need to use your own estimate of EPS to calculate the new TTM PE the day after earnings. You can’t fight the big boys; far better to figure out what they’re doing and hitch a ride.

Hope this is useful to somebody.

http://ycharts.com/companies/AAPL/pe_ratio#stats=true&zoom=5&comp=price