## DEFINITION of 'Lambda'

The ratio of the percentage change in an option contract's price to the percentage change in the option's underlying price. Lambda is one of the Greeks – a collection of risk measures or risk sensitivities that are frequently used in options and derivatives analysis. Each Greek measures the sensitivity of a value in relation to a small change in an underlying parameter. Lambda measures the change in option premiums for a percentage point change in its implied volatility. When the lambda value is high, the price of an option will be more sensitive to small changes in volatility. Conversely, when lambda is low, changes in volatility will have less impact on the option's value.

## BREAKING DOWN 'Lambda'

Lambda is one of many Greeks used in determining and managing risk in options and derivatives trading and investing. The most common Greeks used are: Delta, which measures the rate of change of option value in response to changes in the price of the underlying instrument; Vega, which measures sensitivity to volatility; Theta, which measures the sensitivity of the value against the passage of time; Rho, which measures sensitivity to the interest rate and Gamma, which measures the rate of change in the Delta with respect to changes in the price of the underlying instrument.