Zomma (∂³V/∂S³)

Third-order Greek measuring how gamma changes with the underlying price — the "gamma of gamma".

Definition

The third partial derivative of option value with respect to the underlying spot price. Zomma quantifies how rapidly gamma changes as spot moves, making it essential for dynamic hedging of portfolios with concentrated gamma exposure.

Formula
Zomma = ∂Γ/∂S = -(Γ / S) × [ (d₁ / (σ√t)) + 2 ]

Where Γ is gamma, d₁ is the standard Black-Scholes d₁ term, σ is implied volatility, t is time to expiry, and S is spot price. Zomma is typically a very small number and is quoted per unit move in the underlying.

Inputs
spot price strike price time to expiry implied vol
API Field
third_order.zomma
Interpretation
  • Positive zomma: gamma is increasing as spot rises. The option is becoming more convex — delta will accelerate faster on further up-moves.
  • Negative zomma: gamma is decreasing as spot rises. The option's convexity is flattening — delta acceleration is slowing.
  • Near ATM: zomma is near zero at the money (gamma peaks there). Zomma is most significant for OTM options approaching the strike.
  • Dynamic hedging: high absolute zomma means gamma is unstable — re-hedging intervals must be tightened to avoid delta slippage.

Why Zomma Matters

Gamma tells you how much delta will change for a unit move in spot. But gamma itself is not constant — it peaks at the money and falls off as the option moves into or out of the money. Zomma measures this curvature of gamma. For a market maker hedging a large book, zomma determines how quickly their gamma hedge becomes stale after a spot move.

Consider a portfolio that is long gamma near the current spot. As price moves away, gamma declines (zomma is the rate of that decline). If zomma is large, the hedge deteriorates rapidly, forcing more frequent and costly re-hedging. Conversely, if zomma is low, the gamma profile is stable and hedges last longer.

Zomma is particularly relevant around major option expirations when gamma is highly concentrated at a few strikes. A small spot move can shift the gamma profile dramatically, and zomma is the metric that quantifies that instability.

Get Zomma via API

Endpoint
GET /v1/pricing/greeks
Tier
Free
Parameters
  • spot (required) — underlying price
  • strike (required) — option strike price
  • dte (required) — days to expiration
  • sigma (required) — implied volatility (decimal)
  • type (required) — call or put
  • r (optional) — risk-free rate (default 0.05)
  • q (optional) — dividend yield (default 0.0)
Response field
{
  "third_order": {
    "zomma": number,
    "zomma": number,
    "color": number,
    "ultima": number
  }
}
curl -H "X-Api-Key: YOUR_KEY" \
  "https://lab.flashalpha.com/v1/pricing/greeks?spot=550&strike=560&dte=30&sigma=0.18&type=call"
import requests
r = requests.get(
    "https://lab.flashalpha.com/v1/pricing/greeks",
    params={"spot": 550, "strike": 560, "dte": 30, "sigma": 0.18, "type": "call"},
    headers={"X-Api-Key": "YOUR_KEY"}
)
print(f"Zomma: {r.json()['third_order']['zomma']:.8f}")
const params = new URLSearchParams({
  spot: 550, strike: 560, dte: 30, sigma: 0.18, type: "call"
});
const r = await fetch(
  `https://lab.flashalpha.com/v1/pricing/greeks?${params}`,
  { headers: { "X-Api-Key": "YOUR_KEY" } }
);
const d = await r.json();
console.log(`Zomma: ${d.third_order.zomma}`);

Why Zomma Matters for Trading

TL;DR

Zomma is how gamma changes with vol. Long zomma profits when vol and moves rise together — the classic vol-rally trade.

What it measures
∂Γ/∂σ — how gamma changes when IV changes.
What it signals
How much your convexity grows or shrinks in vol shocks.
Why we measure it
Vol doesn't just change vega. It also changes gamma — i.e. how your book rehedges. Zomma captures that.
Who uses it
Vol quants, market makers, structured-product desks.

How to read Zomma

Long zomma
  • Gamma grows when vol grows
  • Convex in joint vol-price spikes
  • Valuable in stress regimes
  • Multi-variable tail hedge
Good for: long-vol tail hedges
Short zomma
  • Gamma shrinks when vol grows
  • Hedging drops off in shocks
  • Short-wing book failure mode
  • Vol-regime trap
Bad for: short-wing books in vol rally
ATM (zomma ≈ 0)
  • Near-ATM zomma is tiny
  • Retail-accessible regime
  • Standard gamma/vega trade
  • Negligible zomma exposure
Flat

Rules of thumb

  • Wing-specific Greek. Zomma lives out of the money. ATM zomma is too small to matter.
  • Pair with vomma. Both are wing convexity measures. Together they describe the out-of-the-money vol topology.
  • Event-sensitive. Major vol regime shifts produce zomma P&L even when spot barely moves.
  • Not retail-managed directly. Managed through strike/DTE selection rather than hedged directly.
  • Structured-products bread and butter. Variance swaps and wing-hedged books care deeply about zomma.