We derive the formula for the unilateral price effects of mergers of two products with linear demand in the general asymmetric situation. The formula uses the same information required to calculate upward pricing pressure in the 2010 Horizontal Merger Guidelines.

Most quantitative tools for assessing competitive effects of mergers rely heavily on recapture ratios (also known as aggregate diversion ratios). Recapture ratios measure the proportion of customers switching away from a product that is captured by other products within the market rather than...