You will often read people talking about 160% implied volatility during 1987 crash. Again, it's "just" a 10% daily volatility (standard deviation) OR 8% daily mean absolut deviation. To keep an intuitive way with numbers, a rule of thumb is: 20% implied volty means 1% daily mean absolut deviation 40% implied volty means 2% daily mean absolut deviation 60% implied volty means 3% daily mean absolut deviation 100% implied volty means 5% daily mean absolut deviation .... It's the simplest way to think about volty. and to understand what does it mean. No broker calculator, no website model needed. Cheers Maw
this is way too low for ETFC. It would never be this low unless it was being acquired or for some reason the stock simply stopped moving. the first numbers seem more accurate. might have been a glitch in IB's system.