Mübariz Hasanov

Is South Korea's stock market efficient? Evidence from a nonlinear unit root test

In this article we re-examine efficiency of the South Koreas stock market, extending recent work of Narayan and Smyth (2004). For this purpose we apply the nonlinear unit root test procedure recently developed by Kapetanios et al. (2003). The nonlinear unit root test rejects the null hypothesis of unit root, suggesting that the South Koreas stock market is not weak form efficient, contrary to the findings of Narayan and Smyth (2004).

Purchasing Power Parity in transition economies: evidence from the Commonwealth of Independent States

This article tests the validity of Purchasing Power Parity (PPP) for Commonwealth of Independent States (CIS) countries. For this purpose we test whether the real exchange rate series of 10 CIS countries vis-à-vis the US dollar follow a stationary process. Considering the fact that the CIS countries have undergone major structural changes during the transition period, in addition to conventional unit root tests, we employ recently developed unit root tests that allow for structural breaks and non-linearities. When possible structural changes and non-linearities are not taken into account, the null hypothesis of unit root is rejected only in two out of 10 series. However, allowing for structural breaks and/or non-linearities in the data generating process results in more rejection of the null hypothesis of unit root. All in all, our results provide evidence in favour of the PPP hypothesis in these transition countries.

Nonlinearities in emerging stock markets: evidence from Europe's two largest emerging markets

Recent developments in time series analysis allow proper modelling of nonlinearities in economic and financial variables. A growing body of research was dedicated to investigation of potential nonlinearities in conditional mean of many economic and financial variables, mainly concentrating in developed economies. However, nonlinearities in financial variables in developing economies have not been fully examined yet. In this article we investigate potential nonlinearity and cyclical behaviour of stock returns in Europes two largest emerging stock markets, mainly in the Greek and Turkish stock markets. Specifically, we use STAR family models, which allow to model nonlinearities in the conditional mean, for modelling monthly returns on stock exchange indices of the Athens Stock Exchange and Istanbul Stock Exchange. Although we find no nonlinearity in conditional variance, we do find strong evidence in favour of nonlinear adjustment of stock returns. It is found that allowing for nonlinearity in conditional mean results in a superior model and provides good out-of-sample forecasts, which contradicts to efficient market hypothesis.

The effects of inflation uncertainty on interest rates: a nonlinear approach

In this article, we investigate the effects of inflation variability on short-term interest rates within a nonlinear smooth transition regression framework. The test results suggest that only the conditional mean of the inflation is a nonlinear process whereas the conditional variance is time variant but linear. Using the square root of conditional variance as a proxy for inflation risk, we estimate Fisher equation augmented with inflation risk. Although the estimated Fisher equations suggest that inflation risk reduces short-term interest rates, we find that the effects of inflation risk on interest rates are regime-dependent. Particularly, we find that the negative effects of inflation variability on nominal rates are greater in low-inflationary regimes when compared to high-inflationary regimes. On the other hand, it is found that both inflation and inflation uncertainty raise the expected inflation effect.

A note on efficiency of Australian and New Zealand stock markets

In this article we re-examine efficiency of the Australias and New Zealands stock markets, extending recent work of Narayan (2005). For this purpose we apply the nonlinear unit root test procedure recently developed by Kapetanios et al . (2003). The nonlinear unit root tests reject the null hypothesis of unit root, suggesting that the both stock markets are not weak form efficient, contrary to the findings of Narayan (2005).

The asymmetric effects of monetary shocks: the case of Turkey

This paper examines whether there is an asymmetry in the effects of positive versus negative and small versus big money supply shocks, and whether the effects of the shocks on output and prices vary over the business cycles in the case of Turkey. Negative shocks to money are found to have greater output and smaller price effects compared to the effects of positive shocks, irrespective of the initial state of the economy. It is also found that monetary shocks of different size affect output growth and inflation rates proportionately. These findings can be interpreted as evidence for the view that the short run aggragate supply curve is convex in such a country like Turkey.

Re-examining purchasing power parity for selected emerging markets and African countries

The validity of Purchasing Power Parity (PPP) is re-examined using data for some emerging market economies and African countries, extending recent works of Doğanlar et al. (2009) and Chang et al. (2010), respectively. For this purpose, we apply new unit root tests that allow for nonlinearities and structural change in the data-generating process. The results of this study suggest that although linear unit root test provides evidence in favour of PPP only in a few cases, the new nonlinear unit root tests suggest that the PPP proposition holds in majority of the sample countries.

Time Series Behaviour of the Real Interest Rates in Transition Economies

Stationarity properties of real interest rates are examined for 21 transition economies. Owing to transaction costs and other frictions, it is quite plausible that we are dealing with potential non-linearities in the real interest rate. Therefore we examine stationarity of the real interest rate allowing for non-linearities and asymmetric adjustment with smooth structural change in the data generating process. Our findings suggest that taking account of non-linearities in the data generating process results in a rejection of the unit root null hypothesis for some countries which seem to be non-stationary according to conventional unit root tests. This finding points to the importance of allowing for both structural breaks and asymmetric adjustment in the real interest rate series of transition countries.