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Gamma (Γ)

Gamma measures how fast delta changes when the underlying moves $1. It's the second derivative of option price with respect to underlying price.

Interactive Gamma Curve

Explore how gamma varies across spot prices. Notice that gamma peaks at ATM and drops off as you move ITM or OTM.

Position:
Days to Expiry30d
1d90d
Implied Volatility50%
10%150%
Long gamma: Delta moves in your favor. Price rises → delta increases. Price falls → delta decreases.
ATM (max gamma)OTMITM+00$70kStrike $100k$130kSpot PriceGamma
Spot Price
$100.0k
Γ per $1k
+0.03
Moneyness
ATM
Risk Level
Low
Γ = +0.03 per $1kIf spot moves $1,000, delta changes by ~0.03

Key Properties

Always positive: For both calls and puts
Highest at: ATM, near expiry
Lowest at: Deep ITM/OTM

Long vs Short Gamma

Long Gamma

Bought options

  • Price rises → you get longer
  • Price falls → you get shorter
  • Movements help you
Naturally "buying low, selling high" - your position adjusts favorably.

Short Gamma

Sold options

  • Price rises → you get shorter (miss upside)
  • Price falls → you get longer (catch downside)
  • Movements hurt you
"Buying high, selling low" - rehedge at worse prices or accept adverse P&L.

Gamma by Position

Position
Gamma
Effect
Long call
+
Delta increases as price rises
Long put
+
Delta decreases (toward -1) as price falls
Short call
Opposite - adverse delta changes
Short put
Opposite - adverse delta changes

Gamma and Time

Gamma increases dramatically as expiry approaches, especially for ATM options. This is called gamma risk - near expiry, small price moves cause large P&L swings for short gamma positions.

The Gamma-Theta Trade-off

High gamma positions have high theta decay. You can't have one without the other:

📈

Long Gamma

Bought options

BenefitProfit from large moves
CostPay theta daily
📉

Short Gamma

Sold options

BenefitCollect theta premium
CostExposed to large moves

Related:

  • Delta - What gamma measures the change of
  • Theta - The cost of carrying gamma