Impact of jumps on returns and realised variances: econometric analysis of time-deformed Levy processes

In order to assess the effect of jumps on realised variance calculations, we study some of the econometric properties of time-changed Levy processes. We show that in general realised variance is an inconsistent estimator of the time-change, however we can derive the second-order properties of realised variances and use these to estimate the parameters of such models. Our analytic results give a first indication of the degrees of inconsistency of realised variance as an estimator of the time-change in the non-Brownian case. Further, our results suggest volatility is even more predictable than has been shown by the recent econometric work on realised variance. (c) 2005 Elsevier B.V. All rights reserved.