Third-order Greek · ∂³V/∂σ³
Ultima: the third derivative of an option to implied volatility
Ultima, sometimes written DvommaDvol, is the change in vomma for a change in implied volatility. It's the outermost of the commonly named Greeks, and almost nobody needs it day to day.
The formula
d₁ = [ ln(S/K) + (r + σ²/2)·T ] / (σ√T)
d₂ = d₁ − σ√T
Ultima = ∂Vomma/∂σ = −(Vega / σ²)·[ d₁·d₂·(1 − d₁·d₂) + d₁² + d₂² ]
Black-Scholes, European options, no dividends. S spot, K strike, T years to expiry, r the risk-free rate, σ implied volatility, N(·) the standard normal CDF and φ(·) its density.
Where it shows up
Ultima tells a volatility trader how their vomma will change after a large move in implied vol, which matters for books of far out-of-the-money options during a volatility shock. It's small and noisy everywhere else.
The family, in order
Vega (∂V/∂σ) → vomma (∂²V/∂σ²) → ultima (∂³V/∂σ³). The same ladder for price is delta → gamma → speed.

Questions
What is ultima in options?
Do traders use ultima?
How does ultima relate to vega?
Not financial advice. This article explains how options and dealer hedging work. It is not a recommendation to buy or sell anything.