A typical gas sales agreement (GSA) also called a gas swing contract, is an agreement between a supplier and a purchaser for the delivery of variable daily quantities of gas, between specified minimum and maximum daily limits, over a certain number of years at a specified set of contract prices....

This paper analyzes the volatility structure of the commodity derivatives markets. The model encompasses stochastic volatility that may be unspanned by the futures contracts. A generalized hump-shaped volatility specification is assumed that entails a finite-dimensional affine model for the...