Firm Size, Commodity Price, and Interdependence Between Firm-Level Stock Prices: The Case of Norwegian Salmon Industry

This study aims to investigate the interdependence between stock prices of salmon firms listed at Oslo Stock Exchange and to evaluate how this correlation is affected by firm size and salmon commodity price. Technically, we apply the Johanseni¯s approach (Johansen, 1991) to test cointegration between stock prices and between individual stock prices and commodity price. The time path of the long-run relationship is further examined by recursive estimations. During the sample period, we fail to confirm a common stochastic trend between the stock prices of salmon firms. This is partly explained by the various responses of firm-level stock prices to the leading firmi¯ stock price, depending on firm size. This may also relate to the differences between salmon stock pricesi¯ responses to commodity price.