The present paper demonstrates, via a rolling sample approach, that the stylized fact of nonlinear dependence in stock returns is quite localized in time, suggesting that market efficiency evolves over time. Given that the rolling sample framework is able to detect periods of...

This paper considers testing that an economic time series follows a martingale difference process. The martingale difference hypothesis has been typically tested using information contained in the second moments of a process, that is, using test statistics based on the sample autocovariances or...

This paper investigates the relationship between external debt and energy access in the Sub-Saharan African countries over the period 1999-2021. Results from the dynamic panel threshold method indicates that the link between external debt and energy access is nonlinear. Moreover, the findings...

This paper develops a novel approach to modeling and forecasting realized volatility (RV) measures based on copula functions. Copula-based time series models can capture relevant characteristics of volatility such as nonlinear dynamics and long-memory type behavior in a flexible yet parsimonious...

The purpose of the study is to examine whether the returns and volatility for Indian exchange rates possess non-linear dependence. Furthermore, an attempt is made through a rolling-window approach to check whether non-linear dependence is time-varying. The study employs approximate entropy...

In this paper we consider testing that an economic time series follows a martingale difference process. The martingale difference hypothesis has typically been tested using information contained in the second moments of a process, that is, using test statistics based on the sample...