Hasdemir,E.Omay,T.Department of Basic English (Prep School)International Trade and LogisticsEconomics2024-07-052024-07-0520191978-303030386-02198-724610.1007/978-3-030-30387-7_62-s2.0-85102352141https://doi.org/10.1007/978-3-030-30387-7_6https://hdl.handle.net/20.500.14411/3932This study examines the fiscal sustainability of 14 European Union (EU) Member countries in the long run. For this purpose, a linear Augmented Dickey Fuller (ADF) and a variety of nonlinear univariate unit root tests are applied to the debt-to-GDP series of the 14 EU Member countries; Belgium, Czech Republic, Denmark, Finland, France, Greece, Hungary, Italy, Netherlands, Poland, Portugal, Romania, Slovakia and Sweden. In addition to that, the nonlinear unit root tests applied in this study are classified according to the source of nonlinearities: (i) time dependent nonlinearity (structural break(s)), (ii) state dependent nonlinearity and (iii) hybrid nonlinearity. Thus, the nonlinearities and their sources in data generating process of debt-to-GDP series of every country can be determined. The findings of this study show that the null of linear unit root cannot be rejected for none of the countries by applying linear ADF whereas it can be rejected as a result of nonlinear unit root tests for considerable number of countries, i.e. 11 out of 14 countries exhibit time dependent nonlinearity, 6 out of 14 exhibit state dependent nonlinearity and 10 out of 14 exhibit hybrid nonlinearity in their relevant data. So, the source of nonlinearities in the relevant data differs according to the country. That is, for testing the fiscal sustainability, the nonlinearities in the data need to be taken into account. Ignoring the nonlinearities in the testing procedure can lead misleading results in the decision of fiscal sustainability in the long run. © 2019, Springer Nature Switzerland AG.eninfo:eu-repo/semantics/closedAccessFiscal sustainabilityNonlinearityUnit root testsConference ObjectQ46581