Semantic Rules, the Law of One Price, Purchasing Power Parity and Exchange Rates: Setting the Record Straight

Semantic rules link purely theoretical terms like “price” and “electron” to things we can measure. Without them, theories cannot be tested empirically. When inappropriate, they produce false rejections. Economists routinely ignore semantic rules. Empirical journal articles essentially never mention them. More to the point, the conventional tests that reject the Law of One Price and Purchasing Power Parity never consider them. As a result, those rejections are unwarranted because such tests use inappropriate semantic rules. Both theories should be restored to not rejected and then retested using the more appropriate semantic rules described here. By using appropriate semantic rules, this paper is able to combine Covered Interest Parity and Purchasing Power Parity into a single theory that links auction markets for financial assets and commodities to auction markets for exchange rates. Using appropriate semantic rules for both theories also explains several puzzles in open economy macroeconomics and opens up broad new vistas for research.

Deviations from the covered interest parity: The role of fundamentals, financial and political turmoil, and market frictions

Recent studies of mature markets on covered interest parity suggest that deviations are mean-reverting, but persistent, particularly after the 2008 crisis (Du et al., 2018). Our study contributes to the literature by modeling the deviations from covered interest rate parity (CIP) of an important emerging-market economy. We focus on Brazilian data, given the importance of its derivative market. One of the strengths of our study is the use of an agnostic approach, based on an automatic model-selection technique that is robust to structural change, the Autometrics algorithm (Hendry and Doornik, 2014), to unveil the possible determinants of CIP deviations from a wide information data set. We show that CIP deviations are highly sensitive to changes in Brazilian federal government total debt, level of reserves, inflation, and degree of trade openness. We also document the existence of instability in the model due to financial and political turmoil. We reach these conclusions based on the algorithm’s intercept correction, which can be seen as a byproduct of our methodology. Finally, we find evidence that, even after correction for fundamentals and instability points, CIP deviations still have persistence, suggesting that market frictions play an important role in the dynamics of CIP deviations.