In an imperfectly competitive industry, differentiated products compete with each other with price rather than quantity as the strategic variable. Several previous studies have employed a generalized Nash Bertrand model: Liang (1989), Cotterill (1994), Cotterill, Putsis and Dhar (2000), and Kinoshita, Suzuki, Kawamura, Watanabe and Kaiser (2001); however, only Liang has explored the theoretical foundations of that model. This paper generalizes the Liang two good model to three goods. A surprising and important result follows. Price conjectural variations do not exist in models with 3 or more goods. Price reaction functions, however, exist in multiple good models. We estimate them jointly with a brand level demand system to evaluate the total impact of a... |