Portfolio effects and firm size distribution : carbonated soft drinks

We use rich brand level retail data to demonstrate that the firm size distribution in Carbonated Soft Drinks is mainly an outcome of the degree to which firms own a portfolio of brands across segments of the market, and not from performance within segments. In addition, while the number of firms in each segment is limited by segment size relative to sunk cost and competition in a segment, idiosyncratic firm effects make some firms more likely to participate in any given segment. This feature of the industry is the key to modelling firm size distribution in Carbonated Soft Drinks.