For a predictable position , the current net wealth increment is conditionally Gaussian with mean and variance . Its exponential-loss multiplier is
Differentiate its quadratic exponent. The unique minimizing position is
The first term is the speculative demand; the second offsets the part of the income correlated with the tradable price increment. Independent period vectors and backward induction justify using this same position at every date. Completing the square gives minimal exponent , where
Therefore hedging a Gaussian income stream with exponential utility has value
The residual variance is ; it disappears for perfectly correlated income.