Strategies Options        "To manage is To Forecast..."
 The Option Trading Website
Accès Site
 
Home  >  Pricing Models  >  Black & Scholes : Gamma Г 

Black & Scholes : Gamma Г
Issued on July 16 2011 par Strategies-options.com

In the Black & Scholes model, gamma Г is just the second derivative of an option price with respect to the spot.
Gamma Г is the second derivative of an option price with respect to the spot.
Gamma is a measure of convexity.



I - Maths behind the convexity

For a call :

Γ = ∂² C / ∂ S²
Γ = ∂ Δ / ∂ S = ∂ (exp ( - q.τ ) . N( d1 ) ) / ∂ S
Γ = exp ( - q.τ ) . ( 1 / ( S σ√τ ) ) . N’( d1 )


For a put :

Γ = ∂² P / ∂ S²
Γ = ∂ Δ / ∂ S = ∂ (exp ( - q.τ ) . N( d1 ) - exp ( - q.τ ) ) / ∂ S
Γ = exp ( - q.τ ) . ( 1 / ( S σ√τ ) ) . N’( d1 )


Call and put gamma are the same !




II - Means and 2D graphs

A weak gamma means a small delta variation for a spot move.



A strong gamma means a great variation in delta for a spot move.





III - 3D graphs



■ Gamma is the same for a call or for a put with the same parameters and variables.
■ Gamma is strong as expiry nears.
■ Gamma is maximum around the strike level
Ditm and Dotm options have little to nil gamma.



Next : Black & Scholes : Theta θ
Previous: Black & Scholes : Delta ∆


Pdf connexes :

- Understanding N(d1) and N(d2) : Risk-Adjusted Probabilities in the Black-Scholes Model
- Black-Scholes Option Pricing Model


OPTIONS PRICING MODEL - INDEX
OPTIONS PRICING MODEL - INDEX
OPTIONS PRICING MODEL - CHAPTER I
OPTIONS PRICING MODEL - CHAPTER II
OPTIONS PRICING MODEL - CHAPTER III

Strategies-options.com
Other articles
- Currency Options Trading Strategies -
€/USD Put Butterfly Spread Strategy Summary
Summary and results EUR USD Put butterfly spread Strategy $ + 1350.
- Other Derivatives -
Turbo Warrant : Volatility sensitivity
Turbos are sensible to implied volatility moves, much less than vanilla options.
- Other Derivatives -
Stability Warrants : A First Attempt
Stability Warrants are listed double knock out options issued by banks
- Advanced Strategies -
Ratio Spreads
Ratio Spreads enable to be wrong on an asset direction.
- Basic Strategies -
Long Put Spread : A First Attempt
Long Put Spread is a fundamental strategy which combines the purchase and the sale of two puts.
- Options 101 -
Asset path simulation
Asset simulation is useful to manage position and to price derivatives.