Quote from riskfreetrading:
Try to understand this because it will help you really understand the magniture of what a worse case can be under normal volty conditions.
If realized vol will be the same as currently implied (42.??), and if the current price of SPY ($82.76) is the top price during the next 38 days, we can say this with ABSOLUTE certainty: SPY will reach a price equal to or LESS than $58.75. That is $24 down (with certainty under the above two conditions which is not unrealistic).
So what people see as dramatic moves are normal moves.
There is chance that what I wrote would be a shock to people. You need to understand why it is fundamental truth of how markets work. If you are shocked or your mind cannot accept it, all it says that they you have not fully put your mind around the market.