Constant versus variable markups: Implications for the law of one price

This paper compares the implications of having constant versus variable markups on the Law of One Price (LOP) by decomposing the good-category level prices into marginal costs of production, markups, and trade costs. Using a trade model, it is shown that the case of constant markups corresponds to log-linear trade regressions, while the case of variable markups corresponds to lin-log trade regressions. Empirical results show that marginal costs of production contribute most to the deviations from LOP for both cases of constant and variable markups; the decomposition of marginal costs further shows that destination-specific quality measures play the biggest role.