Equity market integration in the NAFTA region: Evidence from unit root and cointegration tests

This study examines integration of the three participating equity markets before and after the 1993 passage of NAFTA based on daily, weekly, and monthly data. As expected, unit root tests for the overall period 1988-2001 and the two subperiods, 1988-1993 (pre-NAFTA) and 1994-2001 (post-NAFTA), indicate that stock prices are non-stationary but stock returns are generally stationary for all three markets for all three periods. However, daily, weekly, and monthly equity prices in the three NAFTA countries are cointegrated only for the post-NAFTA period. Similarly, US stock prices are more integrated with both Canadian and Mexican stock prices after the passage of NAFTA. This evidence of increased financial integration and co-movement in NAFTA equity markets after the passage of NAFTA has important implications for policymakers and managers.