The rate at which the gamma of an option or warrant will change over time. More specifically, it is the third order derivative of an options value - once to time and twice to the option's price. Color is part of the group of measures known as the "Greeks" (other measures include delta, gamma and vega) which are used in options pricing models.

Color is used by investors who utilize a gamma-hedging option trading strategy, and provides the investor with information on the gamma of an option per year (the daily figure can be found by dividing the result by the number of days in the year). As the number of days left on the options contract get smaller and smaller, color becomes more volatile and less accurate.