Qual Quant (2013) 47:1077–1084 DOI 10.1007/s11135-011-9584-0 A fractional cointegration analysis of Fisher hypothesis: evidence from Turkey Burcu Kiran Published online: 20 August 2011 © Springer Science+Business Media B.V. 2011 Abstract This paper examines the validity of Fisher hypothesis in Turkey over the period from 1990:01 through 2010:03 by using cointegration and fractional cointegration approaches. The findings from Engle and Granger cointegration test indicate that inflation and nominal interest rate series are cointegrated. Since the conventional cointegration tests do not provide strong evidence on the long run relationship, we also use fractional cointegration definition suggested by Cheung and Lai (J Bus Econ Stat 11:103–112, 1993) which requires only a mean reverting (d < 1) relationship between the series. The results from fractional cointegration tests based on GPH and Robinson methods show that inflation and nominal interest rate series are fractionally cointegrated. These findings support the validity of the Fisher hypothesis in Turkey. Keywords Cointegration · Fractional cointegration · Fisher hypothesis · Inflation · Nominal Interest Rates 1 Introduction The well-known Fisher hypothesis, introduced by Irving Fisher (1930) has been frequently investigated in both theoretical and empirical economics due to its importance. Fisher (1930) maintains that the expected inflation is reflected in the nominal interest rates and the real interest rates are constant. In other words, there should be a long run relationship in the adjustment of nominal interest rate corresponding to changes in expected inflation. If the Fisher hypothesis holds, then short term interest rates will be an efficient predictor of future inflation (Mishkin 1992). More importantly, since monetary policy changes have an impact on financial markets, the effectiveness of monetary policies in a given period may be determined by investigating the Fisher hypothesis. When the monetary policy is effective, nominal inter- est rates tend to move in accordance with the expected rate of inflation which can possibly be B. Kiran (B ) Department of Econometrics, Faculty of Economics, Istanbul University, 34452 Beyazit, Istanbul, Turkey e-mail: kburcu@istanbul.edu.tr 123