Trade Openness and the Weak-Form Efficiency of Emerging Stock Markets

Basu and Morey [Trade opening and the behavior of emerging stock market prices, Journal of Economic Integration 20(1), 2005, 68-92] develop a theoretical model that predicts financial opening without trade reform does not lead to higher weak-form efficiency. The present paper brings their proposition to the data of 23 emerging stock markets. In general, the key results from fixed effects panel regressions support their prediction that trade liberalization, rather than financial openness, matters the most for informational efficiency. However, our empirical findings are not consistent with their postulated mechanisms through which it occurs. Firstly, it is not the official removal of non-tariff barriers that leads to higher stock price informativeness. What really matters for stock market investors is the actual level of economy integration in the reforming country with the world. Secondly, it is not the actual gain in productive efficiency in the real sector that leads to higher weak-form market efficiency. Instead, stock prices incorporate information about the expected gain from trade openness, such as higher future profitability or greater future productivity growth.