Sustainability of external debt: further evidence from non-linear framework

This study investigates sustainability of external debt under a two-step non-linear framework. The first step uses a general linearity test proposed by Harvey and Leybourne (2007) to determine the linearity property of external debt. The second step applies a non-linear ADF unit root test proposed by Kapetanios, Shin, and Snell (2003) on the non-liner processes and the linear ADF test on the linear processes to examine the sustainability of external debt. The analysis of 36 debt and 55 current account ratios identifies strong evidence of non-linearity and sustainability. The results indicate superior performance of the non-linear unit root test over the ADF test in determining the stationary property of the data.