Do Asian stock market prices follow random walks? Evidence from the variance ratio test

1995 ◽  
Vol 5 (4) ◽  
pp. 251-256 ◽  
Author(s):  
Bwo-Nung Huang
2019 ◽  
Vol 12 (2) ◽  
pp. 81 ◽  
Author(s):  
Dzung Phan Tran Trung ◽  
Hung Pham Quang

This paper aims to test the adaptive market hypothesis in the two main Vietnamese stock exchanges, namely Ho Chi Minh City Stock Exchange (HSX) and Hanoi Stock Exchange (HNX), by measuring the relationship between current stock returns and historical stock returns. In particular, the tests employed are the automatic variance ratio test (“AVR”), the automatic portmanteau test (“AP”), the generalized spectral test (“GS”), and the time-varying autoregressive (TV-AR) approach. The empirical results validate the adaptive market hypothesis in the Vietnamese stock market. Furthermore, the results suggest that the evolution of HSX has served as an important factor of the adaptive market hypothesis.


2015 ◽  
Vol 2 (2) ◽  
pp. 89-107
Author(s):  
Saloni Gupta ◽  
Neha Bothra

We conduct tests of the null hypothesis of a random walk at the aggregate level of market indices and disaggregate level of individual shares to the Indian stock market over various data periods and a comparison of two sub-periods namely the pre liberalization and the post liberalization period. For this, we use the Lo-MacKinlay (1988) variance ratio test. Although the oldest test i.e. the serial correlation coefficient test is also applied to the same data to establish the relationship between the two tests but its results are not elaborated in this paper. The strength of this paper lies in the voluminous data base and a powerful testing tool that it makes use of. It is observed that the market is highly inefficient at daily returns level, thus imbibing high degree of predictability in stock returns, and even the weekly returns show the existence of trend. Monthly returns, however, support the random walk hypothesis across all periods. Thus it is concluded that further refinement of reform measures is required.


1998 ◽  
Vol 30 (5) ◽  
pp. 569-578
Author(s):  
David Karemera ◽  
Vera Harper ◽  
Victor Iwuagwu Oguledo

2016 ◽  
Vol 11 (3) ◽  
pp. 75-86 ◽  
Author(s):  
Josephine Njuguna

The purpose of this article is to examine the efficiency of the Tanzania stock market. The study attempts to answer whether the Tanzania stock market is weak-form efficient. The study applies a battery of tests: the serial correlation test, unit root tests, runs test and the variance ratio test using daily and weekly data with a sample spanning from November 2006 to August 2015 for the Dar es Salaam Stock Exchange (DSE) all share index and from January 2009 to August 2015 for the DSE share index. Overall, the results of the market efficiency are mixed. The serial correlation test, unit root test and the runs test do not support weak-form efficiency, while the more robust variance ratio test supports weak-form efficiency for the DSE. The main contribution of the study is that the market efficiency of the Tanzania stock market has increased over the sample period. Keywords: adaptive market hypothesis, efficiency market hypothesis, serial correlations test, unit root test, runs test, variance ratio test, Dar es Salaam Stock Exchange. JEL Classification: G14, G15


2011 ◽  
Vol 9 (4) ◽  
pp. 571
Author(s):  
Regis Augusto Ely

This paper searches for evidence of predictability in the Brazilian stock market using portfolios grouped by sector and firm size with data from 1999 to 2008. I conduct an automatic variance ratio test using wild bootstrap. This methodology eliminates the arbitrary choice of the holding period as well as improves small sample properties. The results suggest (i) stocks from the industrial sector are highly predictable, (ii) stocks from small firms tend to be more predictable than the ones from large firms, (iii) the Brazilian stock market, measured by the Ibovespa index from 1986 to 2008, shows an increase of efficiency since 1994.


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