predictability in returns involves the use of time-series tests for stationarity of return indices and for cointegration between return indices. 1/ The motivation for these tests is that each could potentially provide evidence of strong forms of return predictability. Other weaker forms of predictability will be addressed in Sections Vb and Vc . It should be noted at the outset that the tests in this section use total return indices, rather simple returns which are the first difference in return indices.
Tests for the order of integration of a returnindex will reveal
This paper is a response to the literature that tests for cointegration between national stock market indices. It argues that apparent findings of cointegration in other studies may often be due to the use of asymptotic, rather than small-sample, critical values. In fact, economic theory suggests that cointegration is unlikely to be observed in efficient markets. However, this paper finds some evidence for the long-horizon predictability of relative returns, and the existence of “winner-loser” reversals across 16 national equity markets. A conclusion is that national stock market indices include a common world component and two country-specific components, one permanent and one transitory.
This paper examines the evidence for the common assertion that the volatility of emerging stock markets has increased as a result of the liberalization of markets. A range of measures suggests that there has been no generalized increase in volatility in recent years; indeed, it appears that volatility may have tended to fall rather than rise on average. The paper also tests for the predictability of long-horizon returns in emerging markets. While there is evidence for positive autocorrelation in returns at horizons of one or two quarters, the autocorrelations appear to turn negative at horizons of a year or more. However, the magnitude of the apparent return reversals is not that much larger than reversals in some mature markets. One interpretation of the results would be that emerging markets have not consistently been subject to fads or bubbles, or at least no more so than in some industrial countries. In general, the liberalization and broadening of emerging markets should lead to a reduction in return volatility as risk is spread among a larger number of investors.