Are Asian stock markets efficient? Evidence from new multiple variance ratio tests

This paper tests for the martingale hypothesis in the stock prices of a group of Asian markets. We use new multiple variance ratio tests based on the wild bootstrap and signs. These are non-parametric finite sample tests, which do not rely on large sample theories for statistical inference. This paper also presents Monte Carlo results that these non-parametric tests show superior small sample properties to those of the conventional Chow–Denning test. Both weekly and daily data from 1990 are considered, while moving sub-sample windows are used for the latter to control the sensitivity of the results to a particular sample period. It is found that the Hong Kong, Japanese, Korean and Taiwanese markets have been efficient in the weak-form. The markets of Indonesia, Malaysia and Philippines have shown no sign of market efficiency, despite financial liberalization measures implemented since the eighties. We have also found evidence that the Singaporean and Thai markets have become efficient after the Asian crisis. In general, the results point toward the notion that the pricing efficiency of a market depends on the level of equity market development as well as the regulatory framework conducive of transparent corporate governance.