Below is the weekly chart of SPY (S&P500). I’ve calculated the percent increases to new highs from each previous peak. The average increase from the previous high is 2.6% over the last 3 times the index made a new all time high before pulling back. That would translate to a price of about 309 for when the index makes another move lower. Although I probably won’t short at these prices, I definitely would not be buying anything here since the risk/reward is atrocious.
Buyers can look for a retest of 300 before buying, and aggressive sellers can look for a move down to 300 for a quick trade.