This is primarily based on observation. I am testing this Hypothesis, but I have noticed whenever the price is overextended at least 10% above its 50 MA we see a dip of at least 2-5 percent. I could be wrong but if this is the case, SPY has lots more room to go up. I am seeing this reach at least 442. My original target was 420 or 425, but SPY has been consolidating in this area holding this current price range giving the 50MA time to breath.