The primary purpose of this article is to conduct the Fourier Nonlinear Unit Root Test to check Purchasing Power Parity (PPP) for seven cryptocurrencies traded in seventeen countries from 2010 to 2021. The unit root test provides moderate support to the PPP hypothesis when we use each...

This study offers a novel examination of the mean-reversion properties of the current account balances, expressed as a percentage of GDP, for the Asian-5 economies: Indonesia, Korea, Malaysia, the Philippines, and Thailand. While prior studies mainly employed traditional unit-root tests, our...

Natural gas plays important role in the global energy sources, hence understanding its price behavior is important to various economic agents. This study examined whether rational bubbles existed in the three major natural gas markets by employing Fourier unit root tests and a nonparametric rank...