Product Differentiation and Firm Size Distribution: An Application to Carbonated Soft Drinks

Using brand-level retail data, the firm size distribution in carbonated soft drinks is shown to be an outcome of the degree to which firms have placed brands effectively (store coverage) across vertical (flavour, packaging, diet attributes) segments of the market. Regularity of the firm size distribution is not disturbed by the nature of short-run brand competition (turbulence in brand market share) within segments. Remarkably, product differentiation resulting from firms acquiring various portfolios of product attributes and stores in market evolution determines the limiting firm size distribution.