A Comment on “Price-Endings When Prices Signal Quality”
评论了Stiving（2000）关于价格尾数的模型，指出原模型排除了合理的分离均衡且未确保各细分市场需求非负；修正后得到71%的价格以9结尾，仅12%以0结尾，与原结果相反。
Stiving (2000) proposes an interesting model to explain price-endings. His analysis shows that even when customer demand increases at 9-ending price points, certain firms that use high prices to signal quality are more likely to set those prices at round numbers. This comment raises two issues about the model. First, it appears that the original paper imposes a condition that has the effect of eliminating a broad range of legitimate separating equilibria from the analyses. Second, it appears that the original model does not include constraints to ensure that the demand for each market segment will be nonnegative. When these constraints on demand are included, one obtains different aggregate demand curves, which leads to different equilibrium prices. Using the revised model and analysis, we find that 71% of the prices end in 9 and only 12% in 0. This contrasts with only 3% ending in 9 and 58% ending in 0 for the original study. Therefore, 9-endings still prevail even though high prices can be used by firms to signal high quality.