The article presents a new theory for analyzing mergers in industries where both buyers and sellers have market power. This theory is different from the traditional method of using the Hirschman–Herfindahl Index (HHI). The researchers found that the more inelastic the demand for a product, the more captive production and consumption affect price margins. They applied this theory to the merger of Exxon and Mobil's gasoline refining and retail assets in the western United States.