PRODUCT VARIETY AND DEMAND UNCERTAINTY: WHY MARKUPS VARY WITH QUALITY

We demonstrate that demand uncertainty can explain equilibrium product variety in the presence of sunk costs. Product variety is an efficient response to uncertainty because it reduces the expected costs associated with excess capacity. We find that within the firm's product line, the highest quality product has the highest profit margin but the lowest percentage margin, while the lowest quality product has the highest percentage margin but the lowest absolute margin. Both of these relationships are consistent with evidence available from marketing studies.