We propose recent functional data analysis techniques to study the intra-daily volatility.
In particular, the volatility extraction is based on functional principal components and
the volatility prediction on functional AR(1) models. The estimation of the
corresponding parameters is carried out using the functional equivalent to OLS. We
apply these ideas to the empirical analysis of the IBEX35 returns observed each _ve
minutes. We also analyze the performance of the proposed functional AR(1) model to
predict the volatility along a given day given the information in previous days for the
intra-daily volatility for the firms in the IBEX35 Madrid stocks inde