Options valuation or pricing models describe mathematically how a set of input parameters – typically underlying price, strike price, time to expiration, interest rate, and volatility – combine to determine a theoretical value of an option.
CQG offers seven models that serve as the framework for valuing options:
Key to terms
Term |
Definition |
TheoV |
option theoretic value |
sigma, σ |
volatility of the relative price change of the underlying stock price |
ImpV |
implied volatility |
Greeks |
Partial derivatives of the option price to a small movement in the underlying variables. Main Greeks are delta, gamma, theta, vega, rho. |
Delta, ∆ |
delta is the first derivative of the option price by underlying price |
Gamma, Γ |
gamma is the second derivative of the option price by underlying price |
Vega |
vega is the first derivative of the option price by volatility |
Theta, Θ |
theta is the first derivative of the option price by time to expiration |
Rho, ρ |
rho is the first derivative of the option price by interest rate |
N(x) |
cumulative normal distribution function |
n(x) |
normal distribution function , |
S |
underlying price |
X |
strike price of option |
r |
risk-free interest rate |
T |
option time to expiration in years |
σ |
volatility of the relative price change of the underlying instrument |
b |
the cost-of-carry rate of holding the underlying security |
For further reading, we suggest:
• The Complete Guide to Option Pricing Formulas. ISBN 0071389970.
•Options, Futures, and Other Derivatives. ISBN 0132164949.
• Option Volatility and Pricing Strategies. ISBN155738486X.