4
votes
2answers
170 views

Indexes/stocks with flat implied volatilities

After the 1987 crash, the S&P500 index implied volatility changed from nearly flat to negatively sloped. According to Rubinstein the Black-Scholes model was not so wrong when applied to the ...
6
votes
3answers
325 views

What is an acceptable error on implied volatility?

Given an implied volatility surface (on equity indexes) and a calibrated model, what is the range of error on implied volatility a trader would accept ? This obviously depends on the model used to ...
0
votes
0answers
122 views

Getting the actual distribution of a stock price at time T using implied volatility [duplicate]

Possible Duplicate: How to derive the implied probability distribution from B-S volatilities? Let's assume a stock price S, with volatility $\sigma$ constant, no dividend, and risk free ...