Since the early 1990s volatility indices, such as VIX by CBOE, served as market sentiment
barometers as well as important pieces of information for asset allocation decisions.
The later launch of first futures and exchange traded option contracts on them in 2004
and 2006, respectively, made volatility investable in an intuitive, direct and standardized
way, as it did not exist before. Due to the negative correlation between volatility and the
underlying market returns, investing in it can reduce market downside risks and improve
portfolio efficiency. Furthermore, implicit volatility exposure can be hedged or directional
trading of volatility levels is possible.
In this thesis we take a look on the new calculation methodology of the VIX index as a
representative of the model-free implied volatility class and discuss possible option pricing
approaches within three different models. Whaley exemplarily suggests Black-76 model,
whereas Gr¨unbichler & Longstaff (1996) utilize the mean-reverting CIR process to model
VIX and price options on it. Both consider VIX or its futures prices as standalone objects,
whose dynamics are specified directly.
In the third approach the major US equity index S&P500, whose implied volatility is
measured by VIX, is described by the Heston model. Taking VIX’s calculation methodology
into account, the process governing VIX can then be consistently derived as the
square root of the conditional expectation of the forward looking realized variance of the
S&P500 returns.
Especially in the last approach the introduced affine processes and their differential characteristics
turn out to be crucial in deriving the characteristic function of VIX2 needed
for pricing options.
Following the respective pricing formulas, delta hedge ratios as well as other sensitivities
are derived. Having calibrated the models, the effectiveness of the delta hedging strategy
for VIX options is analysed on several market data sets. Calibration and hedging results
are compared, allowing for further suggestions for practice.