Although the General Agreement on Trade and Tariffs prohibits discriminatory import tariffs, GATT rules include means by which this prohibition can be circumvented. The previous literature use static models to show that discriminatory tariffs increase welfare. In a dynamic model, this is not necessarily true. For example, with consumer switching costs, current market share is valuable. In this case, discriminatory tariffs are higher for firms with a higher market share. In expectation of such policies, firms price less aggressively. If switching costs are significant relative to exporting country asymmetries then this adverse affect on incentives can result in lower importing country welfare. This suggests that it might be in the interests of importers to abide by the GATT MFN principle.
JEL classification: F12, F13, L13
Keywords: discriminatory tariffs, endogenous protection, switching costs, market share.