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This paper propose a new short-term interest rate model having a dif-ferent nonlinear drift function and the same diusion coecient with Chanet al.(1992) model. The fractional polynomial power of the drift functionin our model is linked to the local volatility elasticity of the diusion coef-cient. While the nonlinear drift function estimated by A¨ıt-Sahalia (1996a)and others has a feature that higher interest rates tend to revert downwardand low rates upward, the drift function estimated by our nonlinear modelshows that higher interest rate mean-reverts strongly, but, medium rates hasalmost zero drift and low rates has a very small drift. This characteristiccoincides the empirical result based on the nonparametric methodology byStanton (1997) and the implication by the scatter plot of the short rate data.