Nonparametric Estimation of the Diffusion Coefficient via Fourier Analysis, with Aplication to Short Rate Modeling

In this paper a new fully nonparametric estimator of the diffusion coefficient is introduced, based on Fourier analysis of the observed trajectory. The proposed estimator is proved to be consistent and asymptotically normally distributed. After testing the estimator on Monte Carlo simulations, we use it to estimate an univariate model of the short rate with available interest rate data. Data analysis helps shedding new light on the functional form of the diffusion coefficient.