An issue that I have repeatedly mulled over is how to best account for this "discontinuous" change in the value of SPY technically. For example, if SPY now gaps below an important low that held the prior day, it is not necessarily a break of support. Also, things such as Fibonacci retracements and pivot calculations are "thrown off." I imagine most software considers the gap to be a valid price change, as other alternatives make even less sense.
My tenative conclusions are :
(1) This is another reason to trade the SPX futures rather than the SPY ETF.
(2) Shortly after the distribution occurs, I should base trades on the behavior of the SPX futures (if I have access to real-time data) or the SPX cash otherwise. In a few days to a week, this effect will diminish as long as I am referring only to short-term swing highs and lows.
I did a search for threads on this subject but didn't come up with what I was looking for.