Turbulence in the Swedish Beer Market.

In this case study of the Swedish beer market we relate the volatility of firms' market shares to changes in their products' market shares. We focus on the four leading firms' product portfolios, and in particular the development of the market shares of old, newly introduced, and withdrawn products. Most of the long run fluctuations are due to trends in sales of old products whereas the short run fluctuations arise from unstable development of new products. In general, firm market shares are more stable than market shares of individual products. We explain the greater stability of firm market shares with firms' ability to introduce and withdraw products from their portfolios. We find that firms are more likely to introduce a product when their market shares have been falling. The industry provides a benchmark of the turbulence in market shares due to exogenous changes in consumer preferences, as advertising is severely restricted and the importance of prices is minor.