Deriving the exact equations for Delta, Gamma and the unnamed third price-derivative of a call option
An underlying knowledge of options is assumed. This post is intended to demonstrate various parameters that will be used in a future post.
Using the Black-Scholes model for options pricing, a call option price is:
Where Φ(x) is the cumulative probability function of a standardised normal variable.
Using partial derivatives, the rate of change of c with respect to S will be derived. This rate of change is commonly labelled Δ, Delta.
The normalised probability function and cumulative probability function are related in the following manner:
Substituting this into the partial derivative of c, the following results:
Further manipulation of the above equation can yield the second derivative of c with respect to S, commonly labelled Gamma or Γ.
The standardised normal probability distribution function and its derivative are of the following form:
Substituting the derivative of the normal probability distribution function into the second derivative of c with respect to S,
Click here to see skipped steps in this derivation
The third derivative of C with respect to S is not given a Greek symbol. Using the above result,
Click here to see skipped steps in this derivation
In summary,
Using the Black-Scholes model for options pricing, a call option price is:
Where Φ(x) is the cumulative probability function of a standardised normal variable.
Using partial derivatives, the rate of change of c with respect to S will be derived. This rate of change is commonly labelled Δ, Delta.
The normalised probability function and cumulative probability function are related in the following manner:
Substituting this into the partial derivative of c, the following results:
Further manipulation of the above equation can yield the second derivative of c with respect to S, commonly labelled Gamma or Γ.
The standardised normal probability distribution function and its derivative are of the following form:
Substituting the derivative of the normal probability distribution function into the second derivative of c with respect to S,
Click here to see skipped steps in this derivation
The third derivative of C with respect to S is not given a Greek symbol. Using the above result,
Click here to see skipped steps in this derivation
In summary,
Labels: finance, mathematics
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