This study examines the convergence hypothesis of natural gas price series of Russian Federation and USA using both linear and nonlinear time series techniques Russian Federation and USA during the period of 1991-2011. Although the linear Augmented Dickey Fuller (ADF), Philips Perron (PP), test provide evidence of the existence of a unit root, which means that the series are nonstationary, KPSS test result support the null hypothesis of existence of the stationary series. A nonlinear test as an alternative approach to investigate whether there are nonlinearities in the series is also taken into consideration. KSS, the nonlinear testing procedure provide some supportive evidence of a nonlinear price convergence among the Russian Federation and USA.
