Abstract
This
article attempts to identify the best model of the short term interest rates
that can predict its stochastic process over time. We studied nine different
models of the short term interest rates. The choice of these models was the aim
of analyzing the relevance of certain specifications of the short term interest
rate stochastic process, the effect of mean reversion and the sensitivity of
the volatility to the level of interest rate. The yield on US three months
treasury bills is used as a proxy for the short term interest rates. The parameters
of the different stochastic process are estimated using the generalized method
of moments. The results show that the effect of mean reversion is not
statistically significant and that volatility is highly sensitive to the level
of interest rates. To further study the performance prediction of the
intertemporal behavior of the short term interest rate of the various models;
we simulated their stochastic process for different periods. The results show
that none of the studied models reproduce the actual path of the short term
interest rates. The problem lies in the parametric specification of the mean
and volatility of the diffusion process. To further study the accurate
parametric specification of the interest rate stochastic process we use a
nonparametric estimation of the drift and the diffusion functions. The results
prove that both should be nonlinear.