Index tracking requires building a portfolio of stocks (a replica) whose behaviour is as close as possible to that of a given stock index. Typically, much fewer stocks should appear in the replica than in the index, and there should be no low frequency (persistent) components in the tracking...

This paper is an empirical study of the motives for charitable donations, based on a unique data set of the English National Opera. Merging all their box office and fundraising data, our data set not only contains individuals’ donations, but also their opera attendance and all the fringe...