Hot answers tagged spx
If you look at tick data, you will probably get an even better analysis. However, vix correlation tends to be negative with spx but remember that this is generally more true for when spx tanks. When spx goes up, the correlation isn't as strong. Why? People panic after a drop, therefore leading to people buying options. They don't care about black scholes ...
The VIX is designed to "represent the implied volatility of a hypothetical at-the-money [SPX] option with exactly 30 days to expiration." (via the CBOE) The calculations are available from the CBOE in this white paper. Note that your question is wrong -- it is the implied volatility, not the vega. Moreover, you wouldn't predict a change in vega (which is a ...
Generally speaking, volatilities at all points of the vol surface are (positively) correlated in both empirical and theoretical models. So if you feel you have a prediction strategy for the VIX, you have an associated directional prediction for other volatilities, and you can take advantage of that. Directional volatility bets are most often expressed (as ...
I don't know if I understand your question correctly but the procedure how to calculate ATM option prices with publicly available implied volatility indices (like VXO) for the vol parameter can be found in the mentioned paper on pages 5-7: How Students Can Backtest Madoﬀ’s Claims by Michael J. Stutzer (2009)
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